tag:blogger.com,1999:blog-9652949337949671942024-02-21T02:24:16.707-08:00colonoscopy & endoscopyjobs infohttp://www.blogger.com/profile/04994118660262498872noreply@blogger.comBlogger447125tag:blogger.com,1999:blog-965294933794967194.post-80275407255195838832018-01-02T07:23:00.000-08:002018-01-02T07:23:10.324-08:00Carbon dioxide insufflation <div dir="ltr" style="text-align: left;" trbidi="on">
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Gas insufflation is mandatory to ensure good visualisation during colonoscopy. Currently, air is commonly
used for this purpose (Janssens et al. 2009). However, significant amounts of air can be retained
in the GI tract (Bretthauer et al. 2003) causing pain and discomfort for the patient. Pain associated
with colonoscopy has been identified as a major barrier to participation in CRC screening</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Randomised trials have shown that carbon dioxide insufflation significantly reduces abdominal pain
and discomfort in patients undergoing colonoscopy and flexible sigmoidoscopy (Bretthauer et al.
2002a; Bretthauer et al. 2002b; Sumanac et al. 2002; Church & Delaney 2003; Wong et al. 2008)</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Side effects of C02 insufflation were not detected in unsedated patients in two randomised studies
identified in the present literature search and involving 350 patients (Bretthauer et al. 2002b; Bretthauer
et al. 2005). Slightly elevated end-tidal C02 levels were detected in sedated patients in the latter
study, but only 52 sedated patients were included in the study and patients with chronic obstructive
pulmonary disease, as well as patients with known C02 retention, were excluded.</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Since carbon dioxide is an inert gas that cannot form a combustible mixture with hydrogen and methane,
C02 insufflation will avoid the very rare risk of explosion during sigmoidoscopy or colonoscopy</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Following incomplete colonoscopy, an alternative examination is frequently required. Provided adequate
facilities are available, same-day CT or MRI colonography, or, in appropriate cases, doublecontrast
barium enema would be desirable. However, same-day radiologic examination following
colonoscopy frequently yields suboptimal quality when air insufflation is used for colonoscopy, due to
retained air in the colon. If CO2 insufflation has been used, same-day radiologic imaging is generally
feasible with appropriate quality. This avoids the necessity of scheduling the additional radiologic examinations
on another day and further colon cleansing (Phaosawasdi et al. 1986; Rodney, Randolph &
Peterson 1988)</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">In light of the above evidence and considerations: </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> Carbon dioxide insufflation is recommended for colonic endoscopic procedures (I - A).Rec 5.31</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> Carbon dioxide insufflation should be avoided in patients with COPD, known C02 retention or otherwise
reduced pulmonary function (VI - A).</span></div>
</div>
மாங்குளம் AVM.பாஸ்கரன் M.Techhttp://www.blogger.com/profile/14275260072192866587noreply@blogger.com0tag:blogger.com,1999:blog-965294933794967194.post-17533340839497608562017-12-27T07:20:00.000-08:002017-12-27T07:20:08.872-08:00Sedation and comfort <div dir="ltr" style="text-align: left;" trbidi="on">
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;">Flexible sigmoidoscopy </span></b></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Although flexible sigmoidoscopy is not currently recommended by the EU for colorectal cancer screening,
previous results of ongoing trials indicate that screening is feasible and the procedure is well accepted
by screenees ( UK Flexible Sigmoidoscopy Screening Trial Investigators 2002; Segnan et al. 2005;
Weissfeld et al. 2005; Segnan et al. 2007; Hoff et al. 2009). No sedation for FS was used in these
studies</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;">Colonoscopy </span></b></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Colonoscopy can be an uncomfortable and distressing experience. These adverse effects can be reduced
by careful patient preparation and sedation. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Sedation improves patient tolerance of colonoscopy, particularly sedation using propofol combined
with other sedative agents such as midazolam and analgesics such as pethidine and fentanyl
(McQuaid & Laine 2008) (I). However, excessive sedation is considered to be an important contributor
to cardio-respiratory related deaths following endoscopy in high-risk patients, particularly the elderly</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">According to Rex (Rex 2000b), most of the risk of colonoscopy is related to sedation. Cardiorespiratory
complications are infrequent for patients without known heart or lung disease, but monitoring
of oxygenation and blood pressure should be performed for all sedated patients.</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Although hypoventilation, cardio-pulmonary events and vasovagal reactions may be related to pain
and distension caused by the endoscopic procedure, in most cases they are more closely associated
with the use of sedatives and opioids. Reduction in risk for these reactions has been observed in a
study aimed to determine the incidence of such events when sedation is given only as required. All
procedures in this study were performed by senior gastroenterologists with optimal equipment and
nursing staff. Patients undergoing colonoscopy without sedation had less decline in blood pressure
and fewer hypoxic episodes than sedated patients (Eckardt et al. 1999) </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Heavily sedated patients are more difficult to turn, and this may compromise caecal intubation and
mucosal visualisation.</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">The available evidence indicates that the quality and safety of colonoscopy in patients that receive
propofol sedation is comparable to that in patients receiving light, conscious sedation (or no sedation),
provided patients given sedation are assessed properly prior to their procedure (McQuaid & Laine
2008; Singh et al. 2008) </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Propofol seems to be better than benzodiazepines or narcotics on recovery, discharge time and patient
satisfaction and equivalent on procedure time, caecal intubation rate and adverse events (I).
However, in many countries an anaesthesiologist is required for propofol administration.</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">It is recommended that there be local policies and processes in place to optimise sedation and patient
support in order to maximise tolerance and minimise risk of complications</span></div>
<a name='more'></a><br />
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">The following categories and data relevant to sedation should be monitored: </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">1. No sedation; </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">2. Conscious sedation and substances used; </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">3. Propofol sedation or general anaesthesia, and substances used; and </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">4. Insufflation gas: air or C02</span></div>
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><b>Auditable outcomes:</b> Sedation levels, patient feedback on comfort, dignity and privacy, and adverse
incidents related to sedation, including use of reversal agents. </span></div>
</div>
மாங்குளம் AVM.பாஸ்கரன் M.Techhttp://www.blogger.com/profile/14275260072192866587noreply@blogger.com0tag:blogger.com,1999:blog-965294933794967194.post-53475545989509819052017-12-20T07:17:00.000-08:002017-12-20T07:17:13.532-08:00Image enhancing technology <div dir="ltr" style="text-align: left;" trbidi="on">
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">There is conflicting evidence regarding the potential for narrow band imaging (NBI), Fuji Intelligent
Chromo Endoscopy (FICE), and other techniques of image processing commonly referred to as “virtual
chromoendoscopy” to improve detection and characterisation of high-risk lesions. One trial showed an
increase in the detection rate of diminutive adenomas (Inoue et al. 2008). There was no difference in
adenoma detection rates using NBI technique compared to white-light colonoscopy reported by other
published trials (Johanson 2006; Rex 2006; Kaltenbach et al. 2008; Kaltenbach, Friedland & Soetikno
2008; Adler et al. 2009)</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">The use of autofluorescence was associated with a higher polyp detection rate compared with conventional
endoscopy in one study, although the observed improvement was mainly attributable to an increased
diagnostic yield of diminutive adenomas (Matsuda et al. 2008; Mayinger et al. 2008;
McCallum et al. 2008)</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Studies comparing the performance of colonoscopy with high definition versus standard colonoscopes
did not show an increase in the detection rate of adenomas or hyperplastic polyps when using highdefinition
instruments (East et al. 2008; Pellise et al. 2008; Burke et al. 2009)</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">The results of diagnostic accuracy studies showed better accuracy of NBI colonoscopy compared to
standard colonoscopy in differentiating between neoplastic and non-neoplastic lesions (Su et al. 2006;
Katagiri et al. 2008) (III). In the recent Cochrane review of chromoendoscopy, it was suggested that
NBI may become the gold standard in enhanced techniques for detection of colorectal lesions, but
with the advantage of reduced procedure time compared to chromoendoscopy. One trial comparing
diagnostic accuracy of NBI with chromoendoscopy on 99 Patients has been retrieved (Tischendorf et
al. 2007). The study did not find a significant difference in accuracy between the two technologies for
the differentiation of neoplastic vs. non neoplastic lesions. Further trials comparing NBI and chromoendoscopy
are needed. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Further experience and evidence about efficacy, benefits and potential adverse effects, as well as
cost-effectiveness, are required before additional technologies can be recommended for routine, panEuropean
use in colorectal cancer screening and diagnosis. Particularly in the screening context, improvements
in detection and diagnosis may be accompanied by unacceptable decreases in specificity,
and/or disproportionate, unacceptable increases in cost, measured both in human and financial resources. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">After sufficient standardisation of procedures and protocols in feasibility studies, pilot studies conducted
in the framework of population-based screening programmes, and based on a randomised
public health policy, could provide appropriate evidence to justify future recommendations for widespread
implementation of new technologies. </span></div>
<a name='more'></a><br />
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">In view of the above it is recommended that: </span></div>
<br />
<ul style="text-align: left;">
<li style="text-align: justify;"><span style="font-family: Times, Times New Roman, serif; font-size: large;">The provision and maintenance of equipment in the endoscopic unit should be carefully managed
based on local guidelines that comply with relevant national and pan-European guidelines containing
accepted, published recommendations and standards. </span></li>
<li style="text-align: justify;"><span style="font-family: Times, Times New Roman, serif; font-size: large;"> Flexible video endoscopes and the facility for focal application of dye to the lesion should be used
in colorectal cancer screening (III – B).Rec 5.12 </span></li>
<li style="text-align: justify;"><span style="font-family: Times, Times New Roman, serif; font-size: large;"> The volume of equipment should match the demand put upon it to maximise efficiency and avoid
patient delays (VI - B).Rec 5.11 </span></li>
<li style="text-align: justify;"><span style="font-family: Times, Times New Roman, serif; font-size: large;"> There should be an adequate supply of accessories suited to the endoscopic interventions undertaken
within the unit (VI - B).Rec 5.13</span></li>
<li style="text-align: justify;"><span style="font-family: Times, Times New Roman, serif; font-size: large;"> Use of re-usable accessories should be based on national policy (VI - B).Rec 5.14 </span></li>
<li style="text-align: justify;"><span style="font-family: Times, Times New Roman, serif; font-size: large;"> There should be properly maintained resuscitation equipment in the endoscopy room and recovery
area (VI - B).Rec 5.15 </span></li>
<li style="text-align: justify;"><span style="font-family: Times, Times New Roman, serif; font-size: large;"> Maintenance of equipment should be undertaken by competent staff (V - A).Rec 5.16 </span></li>
<li style="text-align: justify;"><span style="font-family: Times, Times New Roman, serif; font-size: large;"> There should be regular review of the functioning of all endoscopes, in accordance with manufacturer
specifications and instructions and relevant national or pan-European guidelines (VI - B).Rec
5.17 </span></li>
<li style="text-align: justify;"><span style="font-family: Times, Times New Roman, serif; font-size: large;"> The results of the review should be available at all times in the endoscopy unit (VI - A).Rec 5.18 </span></li>
</ul>
</div>
மாங்குளம் AVM.பாஸ்கரன் M.Techhttp://www.blogger.com/profile/14275260072192866587noreply@blogger.com0tag:blogger.com,1999:blog-965294933794967194.post-80279394517297919392017-12-15T07:16:00.000-08:002017-12-15T07:16:29.796-08:00Chromoendoscopy<div dir="ltr" style="text-align: left;" trbidi="on">
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Widespread application of dye to the lumen of the colon (pan-chromoendoscopy) improves the detection
of diminutive lesions (Brown, Baraza & Hurlstone 2007) (I). However, pan-chromoendoscopy is
time consuming and the extra lesions detected may be unimportant clinically as a significant number
of diminutive lesions may regress (Rother, Knopfle & Bohndorf 2007). The authors of a recent Cochrane
review concluded that selective application of dye to suspicious areas (selective chromoendoscopy)
may be more appropriate during colonoscopy</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">This approach is consistent with the conclusions of a recent international workshop which reviewed
the role of non-polypoid lesions in the aetiology of colorectal cancer. The endoscopist should be skilled
in recognising subtle changes in the appearance of the mucosal surface, particularly alterations in colour,
vascularisation and morphology, to identify suspicious areas requiring dye spraying and to better
detect polypoid lesions. Small patches of mucus may require rinsing to expose underlying suspicious
areas worthy of staining, particularly in the right colon </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Selective chromoendoscopy with dye spraying on the lesion has been shown to be superior to conventional
colonoscopy predicting polyp histology (Pohl et al. 2008) (III). Magnification chromoendoscopy
is more effective than conventional chromocolonoscopy for diagnosing neoplastic colorectal
polyps (Emura et al. 2007)</span></div>
<a name='more'></a><br />
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Expert opinion (VI) suggests that selective chromoendoscopy facilitates: </span></div>
<br />
<ul style="text-align: left;">
<li style="text-align: justify;"><span style="font-family: Times, Times New Roman, serif; font-size: large;"> assessment of the lesion and its borders; </span></li>
<li style="text-align: justify;"><span style="font-family: Times, Times New Roman, serif; font-size: large;"> excision of the lesion and of residual tissue; </span></li>
<li style="text-align: justify;"><span style="font-family: Times, Times New Roman, serif; font-size: large;"> colonoscopy for patients with chronic inflammatory bowel disease; and </span></li>
<li style="text-align: justify;"><span style="font-family: Times, Times New Roman, serif; font-size: large;"> colonoscopy for high-risk family syndromes such as HNPCC. </span></li>
</ul>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Thus for most polypoid and non-polypoid colorectal abnormalities, a flexible high-definition video endoscope
and the facility for selective application of dye (chromoscopy) to the lesion is currently sufficient
for detection and characterisation of high-risk lesions. It is recommended that all but the smallest
flat or sessile lesions be ‘lifted’ with submucosal injection of saline or colloid to facilitate safe
removal (endoscopic mucosal resection). Lesions that do not ‘lift’ should not be removed because they
are more likely to be malignant, and removal is more likely to lead to perforation</span></div>
<div style="text-align: justify;">
<br /></div>
<div>
<br /></div>
</div>
மாங்குளம் AVM.பாஸ்கரன் M.Techhttp://www.blogger.com/profile/14275260072192866587noreply@blogger.com0tag:blogger.com,1999:blog-965294933794967194.post-69186786227870320152017-12-09T07:10:00.001-08:002017-12-09T07:10:31.004-08:00Cleansing and disinfection <div dir="ltr" style="text-align: left;" trbidi="on">
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Patients need to be reassured that decontamination processes are up to date and effective. Guidelines
on cleaning and disinfection of endoscopes and endoscopic devices have been developed by the
ESGE-ESGENA</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">It is recommended that decontamination policies and procedures be compliant with national or panEuropean
guidelines based on accepted, published recommendations and standards and should be
audited against defined indicators. The policies should be available in the endoscopy department and
updated regularly</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;">Kit - technologies for improving insertion of the colonoscope </span></b></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">A variety of endoscope technologies may facilitate caecal intubation and improve patient tolerance.
These include variable stiffness instruments, magnetic tracking devices and wire-guided techniques.</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">A recent meta-analysis (Othman et al. 2009) of variable stiffness colonoscopes identified seven randomised
trials involving 1923 patients: four trials comparing adult variable stiffness colonoscopes with
standard adult colonoscopes in adults, and three evaluating the paediatric variable stiffness colonoscope.
The caecal intubation rate was higher with the use of variable stiffness colonoscopes. The variable
stiffness colonoscope was associated with lower abdominal pain scores and decreased need for
sedation during colonoscopy. Intubation times were unaffected by the variable stiffness colonoscope
(I). The use of variable stiffness colonoscopes is recommended for screening colonoscopy</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">The present bibliographic search did not yield any relevant publications on improvement of completeness
of colonoscopy through wire-guided techniques. This new technology has been investigated in
endoscopic management of obstructive tumours </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Two RCTs of the magnetic endoscopic imaging (MEI) device showed improved performance of endoscopists,
both with variable stiffness colonoscopy and with traditional colonoscopy, in terms of patient
tolerance and caecal intubation rates, in particular when little or no sedation is used (Shah et al. 2000;
Shah et al. 2002) (II). The utilisation of magnetic endoscope imaging (MEI) technology may be considered
for patients requiring colonoscopy, particularly when little or no sedation is used </span></div>
<a name='more'></a><br />
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></b></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;">Kit – techniques and technologies to enhance detection, characterisation
and removal of high-risk lesions </span></b></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Image enhancing techniques and technology promise to improve management of high-risk lesions in
three ways.</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">1. First, they might improve the detection of lesions. This will only add value if the lesions detected
are important biologically: identifying more biologically unimportant lesions will add workload and
risk. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">2. Second, they might better define the margins of the lesion to help the endoscopist ensure that it
is completely excised. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">3. Third, they might help characterise the nature of the lesion, helping the endoscopist decide
whether to remove it. This third aspect is of critical importance because it might be more appropriate
not to remove the lesion because of an increased risk of malignancy. Alternatively, if an endoscopist
can safely leave lesions that do not need to be removed, such as small hyperplasic polyps,
considerable time could be saved and small risks of polypectomy avoided. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Essentially there are two approaches to enhanced lesion recognition and characterisation: dyespraying
or chromoendoscopy, and image manipulation techniques or image-enhancing technology. </span></div>
</div>
மாங்குளம் AVM.பாஸ்கரன் M.Techhttp://www.blogger.com/profile/14275260072192866587noreply@blogger.com0tag:blogger.com,1999:blog-965294933794967194.post-82568728452582741822017-12-03T07:06:00.000-08:002017-12-03T07:06:12.455-08:00Scheduling and choice<div dir="ltr" style="text-align: left;" trbidi="on">
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Booking processes must be robust to minimise late cancellations and failures to attend. To increase
the chance of attendance an invitation for a primary screening test should be sent 2–3 weeks before
the procedure is due, with an option for the patient to change the appointment if it is not convenient</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><b>Auditable outcome:</b> Patient feedback on booking processes. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;">Timelines </span></b></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">A timely procedure is not critical in the context of primary screening but it is very important when endoscopy
is performed following a previous positive screening test. A delayed procedure may not be
critical biologically, but it can cause unnecessary anxiety for the screenee.</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">To ensure that patient anxiety is not unnecessarily increased, it is recommended that follow-up
colonoscopy after positive screening be performed as soon as reasonably possible, but no later than
within 31 days of referral (acceptable >90%, desirable >95%) </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><b>Auditable outcome:</b> Time taken from positive screening test to secondary endoscopic examination.
If further pathological information is required before the decision to perform a colonoscopy, then the
maximum and the desirable targets of four and two weeks, respectively, should be timed from the
receipt of the pathology report. The pathology report should be delivered to the screening programme
within two weeks. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;">Environment </span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">The environment should be conducive to a good experience and efficient processing. It should be
physically comfortable, offer privacy and there should be facility to hold private conversations with
screenees and their relatives. The reception and assessment areas should be separate from recovery
facilities </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><b>Auditable outcomes:</b> patient feedback on environment and patient turn around times. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;">During the procedure </span></b></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">There is an increasing body of evidence demonstrating unacceptable miss rates of cancer following
colonoscopy. Miss rates vary between endoscopists suggesting that care with the examination and
technique play a key role in ensuring cancer is not missed.</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Endoscopists must have a mix of technical, knowledge and judgement competencies to identify and
successfully remove high-risk lesions. Ideally they will perform a complete examination quickly, safely
and with minimal discomfort, leaving time to properly inspect the colon, and safely remove and retrieve
lesions. They will identify all abnormal areas, characterise them and make a judgement of what
to do. They will then, if it is appropriate to do so, safely remove and retrieve all neoplastic lesions </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Providing such high-quality and safe endoscopy requires a team approach with appropriate equipment
immediately to hand. The nursing support team must ensure the patient is comfortable and has stable
observations to allow the endoscopist to devote his attention to the procedure. The nurses also provide
important technical support ensuring endoscopy equipment is serviceable and that all the necessary
accessories are readily available. Finally they play an important role supporting the endoscopist
during therapeutic procedures. Both endoscopist and nurse should regularly reflect on their practice
together with pathology and surgical teams in order to optimise patient outcomes. </span></div>
<a name='more'></a><br />
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">High-quality and safe endoscopy also depends on adequate maintenance of equipment, and on an
adequate supply of accessories for the range of procedures undertaken in the department. This
should include equipment to manage complications of excision of high-risk lesions such as bleeding
and in some instances, perforation. Endoscopy equipment is expensive and is subject to frequent and
occasionally heavy use. It is essential that equipment be maintained by competent staff. Maintaining
and repairing old endoscopic equipment is often more expensive than replacing it. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> It is not appropriate for this chapter to provide a manual of how to perform colonoscopy and detect
and remove high-risk lesions. However, there have been significant advances in decontamination
processes, technique and technology in recent years. Because these advances might affect service
provision and patient outcomes, it is considered important to review the evidence for their effectiveness.
</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Technological improvements have promised easier insertion of endoscopes and better visualisation of
the mucosa. However, despite the potential of advances in endoscopic technology, they cannot be
recommended for routine use until they have been demonstrated to be of benefit in clinical practice.
The following sections provide an overview of the current state of these technologies and best practice
for safe, high-quality endoscopy. </span></div>
</div>
மாங்குளம் AVM.பாஸ்கரன் M.Techhttp://www.blogger.com/profile/14275260072192866587noreply@blogger.com0tag:blogger.com,1999:blog-965294933794967194.post-87534227296731662022017-11-27T07:03:00.000-08:002017-11-27T07:03:03.789-08:00Colonic cleansing <div dir="ltr" style="text-align: left;" trbidi="on">
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: x-large;">Inspection of the colon requires careful preparation removing colonic contents to optimise the safety
and quality of the procedure. Ideally there should be no residual stool or liquid in the lumen that could
mask any suspicious area. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: x-large;"><br /></span></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: x-large;">Flexible sigmoidoscopy </span></b></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: x-large;"><br /></span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: x-large;">The ongoing European sigmoidoscopy trials adopted a bowel preparation based on a single enema,
self-administered at home within two hours from the appointment, or, in one case, at the screening
centre.</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: x-large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: x-large;">No studies were found assessing the effect of having the enema performed directly at the screening
centre, although this represents an option that might enhance participation by reducing patient’s concerns
and enhancing engagement. Available evidence from one controlled trial did not indicate that
using two enemas (the first the night before the test and the second two hours before the scheduled
time for the exam) affects participation compared to using a single enema (Senore et al. 1996). Oral
preparation was associated with a reduced participation in a large screening trial, compared to enema
(Atkin et al. 2000). Adding oral preparation to the enema resulted in reduced participation (Bini et al.
2000). </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: x-large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: x-large;">No difference in the proportion of inadequate exams was observed when comparing a single enema
regimen to a preparation using two enemas or to oral preparation. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: x-large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: x-large;">Bowel preparation for screening sigmoidoscopy should involve a single procedure, either enema or
oral preparation (II). A single self-administered enema seems to be the preferred option, but cultural
factors should be taken into account, and patient preferences should be assessed </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: x-large;"><br /></span></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: x-large;">Colonoscopy </span></b></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: x-large;"><br /></span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: x-large;">Data on the impact of different preparation regimens in the context of population screening with
colonoscopy are lacking. A recent systematic review concluded that no single bowel preparation
emerged as consistently superior. Sodium phosphate was better tolerated (Belsey, Epstein & Heresbach
2007), but safety alerts on its use have recently been issued by the US FDA and Health Canada.
The authors identified a general need for rigorous study design to enable unequivocal conclusions to
be drawn on the safety and efficacy of bowel preparations.</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: x-large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: x-large;">Timing of administration of the recommended dose appears important, as it has been established that
split dosing (the administration of at least a portion of the laxative on the morning of the examination)
is superior to dosing all the preparation the day before the test, both for sodium-phosphate and polyethylene
glycol (Aoun et al. 2005; Parra-Blanco et al. 2006; Rostom et al. 2006; Cohen 2010)</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: x-large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: x-large;">A systematic review (Belsey, Epstein & Heresbach 2007) of different bowel cleansing regimens identified
no significant differences other than improved patient tolerance of sodium picosulphate preparations.
Furthermore, there are no preferred methods of assessing the effectiveness of bowel cleansing.
Care must be taken however with some agents (i.e. phospho prep) in certain patient groups, especially
the elderly and those with renal failure, due to potential renal side effects (WHO 2009)</span></div>
<a name='more'></a><br />
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: x-large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: x-large;">To date no single bowel preparation for colonoscopy has emerged as consistently superior over another
(I) although sodium phosphate may be better tolerated and it has been shown that better results
are obtained when the bowel preparation is administered in two steps (the evening before and
on the morning of the procedure) (II). It is therefore recommended that there should be colonic
cleansing protocols in place and the effectiveness of these should be monitored continuously</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: x-large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: x-large;"><b>Auditable outcome:</b> Quality of preparation, patient satisfaction with the bowel cleansing regimen. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: x-large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: x-large;"><b>Accessibility</b>
Several providers of bowel preparation close to the target population should be available when a patient
is required to reach health or community facilities to obtain the preparation. Clear and simple
instruction sheets should be provided with the preparation. For sigmoidoscopy screening, organisational
options include the possibility of having the enema administered at the endoscopy unit</span></div>
</div>
மாங்குளம் AVM.பாஸ்கரன் M.Techhttp://www.blogger.com/profile/14275260072192866587noreply@blogger.com0tag:blogger.com,1999:blog-965294933794967194.post-72180434454635528552017-11-21T07:00:00.000-08:002017-11-21T07:00:17.112-08:00Patient information and consent <div dir="ltr" style="text-align: left;" trbidi="on">
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Information in this context includes information related to the endoscopic procedure and should include
why the procedure is being done, what it involves, preparation for the procedure, and the risks.
The patient should be told what he/she might expect to happen after the procedure (including contact
details in case of emergency) and the plan of aftercare. The patient should be informed about the options
for sedation and how this might affect their perception of the procedure and the associated restrictions
on travelling home.</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">The consent process involves an explanation of the procedure, the potential benefits, the risks and
possible consequences. Consent for endoscopic procedures begins with a recommendation to have the
examination, and ends when the procedure is complete. The individual must have the opportunity to
withdraw consent at any stage during this process. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">The key elements of patient information for endoscopy include: </span></div>
<br />
<ul style="text-align: left;">
<li style="text-align: justify;"><span style="font-family: Times, Times New Roman, serif; font-size: large;"> considerations related to current medications including anticoagulants and antiplatelet agents;</span></li>
<li style="text-align: justify;"><span style="font-family: Times, Times New Roman, serif; font-size: large;">considerations related to previous medical illnesses;</span></li>
<li style="text-align: justify;"><span style="font-family: Times, Times New Roman, serif; font-size: large;"> the benefits of the test;
how to prepare for the procedure (including bowel cleansing); </span></li>
<li style="text-align: justify;"><span style="font-family: Times, Times New Roman, serif; font-size: large;"> the nature of the procedure and what it involves;</span></li>
<li style="text-align: justify;"><span style="font-family: Times, Times New Roman, serif; font-size: large;"> possible adverse events including discomfort and complications; </span></li>
<li style="text-align: justify;"><span style="font-family: Times, Times New Roman, serif; font-size: large;"> what support the patient may need after the procedure, particularly if they are sedated; </span></li>
<li style="text-align: justify;"><span style="font-family: Times, Times New Roman, serif; font-size: large;">and
the importance of not driving or making important decisions after sedation. <a name='more'></a></span></li>
</ul>
<br />
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><b>Auditable outcomes</b>: patient feedback on information and consent processes. These assessments
should ideally be both qualitative and quantitative and make an assessment of the patient experience
judged by the gap between the expectation and actual experience. Withdrawal of
consent should be registered as an adverse clinical incident. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;">Pre-assessment </span></b></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">The purpose of pre-assessment is to identify factors that might influence the outcome of the procedure,
such as anticoagulation and general health status. Pre-assessment also provides an excellent
opportunity to ensure the patient understands the bowel cleansing process and to answer any questions
the patient may have.</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">The nature of the pre-assessment will depend on whether there has been prior contact with an endoscopy
service health professional. If there has been no prior contact with the service, it is advised to
pre-assess the patient several days before the procedure, at least before starting bowel cleansing.
This will enable the procedure to be rescheduled if there are concerns about safety, or for medication
such as warfarin to be withdrawn in sufficient time to allow its anticoagulant effect to wear off. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Available evidence (Bini et al. 2003; Hui et al. 2004; Bernstein et al. 2005; Harris et al. 2007a; Lee et
al. 2008; Tsai et al. 2008) suggests that the following patient-related variables should be identified
and taken into account prior to FS or colonoscopy because they can be associated with more adverse
events, longer duration, and incomplete examination: </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> Use of anticoagulants e.g. warfarin; </span></div>
<br />
<ul style="text-align: left;">
<li style="text-align: justify;"><span style="font-family: Times, Times New Roman, serif; font-size: large;"> Anatomy (female sex); </span></li>
<li style="text-align: justify;"><span style="font-family: Times, Times New Roman, serif; font-size: large;"> Age of patient; </span></li>
<li style="text-align: justify;"><span style="font-family: Times, Times New Roman, serif; font-size: large;"> Prior abdominal surgery;</span></li>
<li style="text-align: justify;"><span style="font-family: Times, Times New Roman, serif; font-size: large;"> BMI; </span></li>
<li style="text-align: justify;"><span style="font-family: Times, Times New Roman, serif; font-size: large;"> Diverticular disease; </span></li>
<li style="text-align: justify;"><span style="font-family: Times, Times New Roman, serif; font-size: large;"> ASA PS (American Society of Anesthesiology classification of Patient Status)2
and information that
may influence type and level of sedation (for those procedures where sedation may be used); and </span></li>
<li style="text-align: justify;"><span style="font-family: Times, Times New Roman, serif; font-size: large;"> Presence of risk factors for endocarditis</span></li>
</ul>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">On the day of the procedure there should be a brief review of the previously collected information and
measurement of basic cardio-respiratory function</span></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><b>Auditable outcomes</b>: Recording and review of adverse clinical events related to inadequate preassessment
(e.g. anticoagulants not stopped or risk factors for endocarditis not identified) </span></div>
</div>
மாங்குளம் AVM.பாஸ்கரன் M.Techhttp://www.blogger.com/profile/14275260072192866587noreply@blogger.com0tag:blogger.com,1999:blog-965294933794967194.post-87914097646921117402017-11-15T06:58:00.000-08:002017-11-15T06:58:09.932-08:00Support services <div dir="ltr" style="text-align: left;" trbidi="on">
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Only rarely will a person undergoing a primary screening procedure require admission to hospital for
further care. Thus it is not necessary to have medical support facilities close at hand. However, services
performing endoscopy in more remote settings must have robust guidelines and processes in
place to enable patients to be resuscitated effectively and be transferred rapidly and safely to a hospital
where surgical services are available. On this basis it is recommended that any screening service,
regardless of setting, should make an assessment of risks and develop the ability to respond to emergencies</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">While there are no absolutes, a case can be made for delivering high-volume screening endoscopy
outside traditional hospital settings to improve the patient experience and to reduce healthcare and
societal costs. In contrast, risk assessments will indicate that colonoscopy following a positive FOBT or
a positive FS is a more complex procedure that is associated with higher risks and should, therefore,
be performed in acute hospital settings. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;">Audit and quality improvement </span></b></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">This section proposes that endoscopy services monitor key outcomes to ensure that a high-quality and
safe service is being provided and to identify areas in need of improvement. Two terms are used for
such outcomes: auditable outcomes and quality indicators. An auditable outcome refers to an outcome
that should be measured, but for which there is not an evidence base to recommend a standard,
such as the comfort of the procedure. A quality indicator is an outcome for which there is a sufficient
evidence base to recommend a standard, such as caecal intubation rate.</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">It is expected that some auditable outcomes will become quality indicators as the evidence base improves,
and that the standards of quality indicators will rise as standards improve. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">On the basis of this, it is recommended that all screening programmes should have processes in place
for monitoring, auditing, reviewing and acting upon key auditable outcomes and quality indicators in
the following areas </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<br />
<ul style="text-align: left;">
<li style="text-align: justify;"><span style="font-family: Times, Times New Roman, serif; font-size: large;">Quality; </span></li>
<li style="text-align: justify;"><span style="font-family: Times, Times New Roman, serif; font-size: large;"> Safety; and </span></li>
<li style="text-align: justify;"><span style="font-family: Times, Times New Roman, serif; font-size: large;"> Patient feedback </span></li>
</ul>
</div>
மாங்குளம் AVM.பாஸ்கரன் M.Techhttp://www.blogger.com/profile/14275260072192866587noreply@blogger.com0tag:blogger.com,1999:blog-965294933794967194.post-67470381763014374412017-11-09T07:59:00.000-08:002017-11-09T07:59:06.715-08:00Patient considerations <div dir="ltr" style="text-align: left;" trbidi="on">
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Patients generally prefer services that are close to home and easily accessible. Thus high-volume
screening endoscopy is probably best situated closer to the population to be screened. In contrast,
level 3 and 4 expertise for removing high-risk lesions is likely to be provided at district and regional
levels respectively. The priority here is the facility and expertise, not proximity. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">When implementing high-volume screening endoscopy consideration should be given to locating services
in convenient locations for patients to maximise engagement in screening</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;">Possible destabilising effect on symptomatic services</span></b></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Unplanned introduction of screening endoscopy (at whatever level) creates additional demand and
may lead to destabilisation of the symptomatic service. Thus, if endoscopy for screening is introduced
alongside symptomatic services, care must be taken to ensue there is sufficient new capacity. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">An assessment of the impact of demand from screening on waiting times for symptomatic patients
should be made to ensure that there is sufficient planned new capacity such that screening does not
lengthen waits for symptomatic patients</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;">Infrastructure and efficiency </span></b></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">The infrastructure requirements for high-volume screening endoscopy need to cater to large numbers
of presumptively healthy people. High-volume screening endoscopy requires efficient booking, assessment
and recovery processes to function effectively without compromising the patient experience.
Thus, it may be advantageous for high-volume screening activities to be separated from routine clinical
endoscopy and follow-up endoscopy of screen-positives. </span></div>
<a name='more'></a><br />
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">It is self-evident that the infrastructure must be adequate. It must include facilities for pre-procedure
assessment and recovery, and must also be designed to allow good patient flow in order to maximise
efficiency (VI - B).Rec 5.9 In addition, a suitable environment will maintain the privacy and dignity of
patients (VI - B).Rec 5.10</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;">Endoscopist and support staff competencies</span></b></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Endoscopists and supporting staff providing endoscopy screening must be competent to deliver high
quality FS or colonoscopy in order to achieve high patient satisfaction and all the required performance
standards relating to quality and safety</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">It is a fundamental requirement of quality assurance that all endoscopists and centres performing endoscopy
should participate in a continuous quality improvement programme, including individual tracking of quality and safety indicators. This should include management plans, for both endoscopists
and staff, for addressing suboptimal quality </span></div>
</div>
மாங்குளம் AVM.பாஸ்கரன் M.Techhttp://www.blogger.com/profile/14275260072192866587noreply@blogger.com0tag:blogger.com,1999:blog-965294933794967194.post-10935632657374112952017-11-03T07:53:00.000-07:002017-11-03T07:53:10.960-07:00The need for sedation<div dir="ltr" style="text-align: left;" trbidi="on">
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">The level of competency to perform high-quality endoscopy and to remove high-risk lesions is also
dependent on the competency of the support team and the available equipment: a highly competent
endoscopist requires equally competent support staff and the right equipment and supplies to perform
the procedure and deal with any problems that might arise (such as clips for uncontrolled bleeding).</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> It is recognised that the methodology does not currently exist to reliably recognise who has achieved
the proposed levels of competence. Thus, until a competency–based assessment process is available
the clinical lead of the service should be satisfied that: </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> the professionals have the necessary competence;</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> the unit has the necessary equipment; and</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> in the event of a serious adverse event, it will be possible to manage the patient locally or transfer
the patient safely to another institution with the expertise and facilities to care for the patient. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">A review of capabilities may identify shortcomings that can be addressed with further training or investment . This training and investment should occur before screening
begins.</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;">The need for sedation</span></b></div>
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">The use of sedation for lower gastrointestinal endoscopic procedures varies between European countries.
Three main patterns are readily discernible:</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> infrequent use of sedation;</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> frequent use of conscious sedation with opiates and benzodiazepines; </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">and
almost exclusive use of deep sedation with propofol or general anaesthesia.</span></div>
<a name='more'></a><br />
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">This variation suggests there is no perfect approach, and emphasises the need to take into account
historic cultural differences when implementing screening endoscopy. A review of the benefits and
risks of sedation showed no clear advantage for a particular approach: conscious sedation provides a
high level of physician and patient satisfaction and a low risk of serious adverse events with all currently
available agents (McQuaid & Laine 2008).</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">The risk of an adverse cardio-respiratory event is lower if the patient does not have sedation (Eckardt
et al. 1999; Rex, Imperiale & Portish 1999; Lieberman et al. 2000; Rex 2000b). Thus, there is less
need for monitoring equipment and recovery facilities if sedation is not used. Therefore sedationless
endoscopy can occur in more remote settings, and it requires lower set-up costs. However, if no sedation
is offered, the patient must accept a higher chance of unacceptable discomfort and the endoscopist
a lower chance of completing the procedure because of patient discomfort. These downsides
might affect the uptake and impact of screening: potential screenees are worried about comfort, and
incomplete procedures may miss important pathology. </span></div>
</div>
மாங்குளம் AVM.பாஸ்கரன் M.Techhttp://www.blogger.com/profile/14275260072192866587noreply@blogger.com0tag:blogger.com,1999:blog-965294933794967194.post-53610097308330256692017-10-28T07:51:00.000-07:002017-10-28T07:51:00.184-07:00QUALITY ASSURANCE IN ENDOSCOPY<div dir="ltr" style="text-align: left;" trbidi="on">
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">The colonoscopist needs to judge whether he/she is competent to remove a lesion and whether it is
safe to remove the lesion in this setting. On the basis of good practice it is recommended that if there
is doubt, the lesion must be appropriately documented and the patient referred elsewhere to have the
lesion removed</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Thus, when considering where endoscopic screening services are to be located, the commissioner
should be aware of how often a patient may need to be referred elsewhere. If it is expected that referral
somewhere else will be a frequent occurrence (perhaps >1% of patients) then it is better to
consider locating the service elsewhere, i.e. where the competence of the available endoscopists
would permit less referral. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">To help in the planning of location of endoscopic services for screening, the following five levels of
competency are proposed. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> Level 0: The operator does not remove any lesions, referring on all patients with any detected
lesions. The operator will be able to biopsy lesions, and pathological material may inform the decision
to refer. Basic level of competency for diagnostic FS but not recommended for screening FS. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> Level 1: Removing lesions <10 mm in diameter at FS. Rationale: larger lesions will indicate a
need for colonoscopy and can be removed when the colonoscopy is performed. Tissue is required
from smaller lesions to decide whether colonoscopy is necessary. Thus any person performing FS
screening should have this level of competency. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> Level 2: Removing polypoid and sessile lesions <25 mm providing there is good access. All
colonoscopists should have this level of competency. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> Level 3: Removing smaller flat lesions (<20 mm) that are suitable for endoscopic therapy, larger
sessile and polypoid lesions, and smaller lesions with more difficult access. Some flat lesions
<20 mm with poor access might be unsuitable for this level. Any person doing colonoscopy for
positive FOBT in a screening programme should have this level of competency. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> Level 4: Removing large flat lesions or other challenging polypoid lesions that might also be
treated with surgery. This is the type of lesion that would not be removed at the first colonoscopy
because of time constraints, if applicable, or because the surgical option needs to be discussed
with the patient. If the patient chooses to have endoscopic therapy, then he/she should be referred
to a level 4 competent endoscopist. This level of competency would be expected of only a
small number of regionally based colonoscopists. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">In the context of colorectal screening and diagnosis in Europe, units only providing Level 0 competencies
are not recommended, because unnecessary endoscopic procedures would be required to remove
small lesions which could have been removed during the initial FS. Furthermore, unnecessary colonoscopies
may be encouraged in the absence of histopathological evaluation of small lesions left in place
during the initial FS. </span></div>
</div>
மாங்குளம் AVM.பாஸ்கரன் M.Techhttp://www.blogger.com/profile/14275260072192866587noreply@blogger.com0tag:blogger.com,1999:blog-965294933794967194.post-84068501148373853882017-10-22T07:47:00.000-07:002017-10-22T07:47:11.267-07:00Effect of screening modality on the provision of endoscopic services for screening <div dir="ltr" style="text-align: left;" trbidi="on">
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Colonoscopy is the recommended test for follow-up investigation for individuals who have tested positive
with other CRC screening tools (FOBT, Flexible sigmoidoscopy (FS), and also in experimental
studies assessing potential screening tools, e.g. DNA faecal markers and CT colonography). Highquality
endoscopy (colonoscopy and flexible sigmoidoscopy (FS)) is also used in some Member States
as a screening tool for colorectal cancer. The frequency of endoscopy when used as a primary screening
tool will be much higher than endoscopy used as a follow-up investigation of another screening
test. Thus the phrase ‘high-volume screening endoscopy’ will be used to refer to endoscopy used as a
primary screening tool and ‘low-volume screening endoscopy’ will be used to refer to follow-up endoscopy.
However, it is recognised that if the test positivity rate in a FOBT screening programme is high
a large volume of colonoscopies will be generated. The key practical difference of these high- and
low-volume populations requiring endoscopy in a screening context is the probability of identifying
and nature of high-risk lesions</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">The setting in which the endoscopic procedure will be performed will be determined by: </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> quality and safety determinants;</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> the need for sedation; </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> patient-oriented factors; </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> possible impact on symptomatic services; </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> infrastructure and efficiency; </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> staff competencies and equipment; and</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> availability of support services. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;">Quality and safety </span></b></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Diagnostic procedures, both flexible sigmoidoscopy and colonoscopy, can be performed safely in diverse
clinical settings. When providing services for a colorectal cancer screening programme, the key
consideration is what facilities and level of competence are required to remove high-risk lesions. Removing
large high-risk lesions safely requires a considerable level of competence and appropriate
support close at hand when a complication occurs. For example, it would be inappropriate to remove
large or difficult high-risk lesions if the colonoscopist is only rarely faced with such a lesion (as in highvolume,
low-risk population screening) or if the procedure is being done in a remote setting. </span></div>
<a name='more'></a><br />
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">The setting in which screening (or follow-up colonoscopy) is established will be determined by the
ability to perform high-quality endoscopy (defined later) and by the probability of finding a high-risk
lesion that is difficult to remove completely and safely. If there is concern about removing the lesion it
is entirely appropriate for the colonoscopist to leave it (and perhaps tattoo it) and refer the patient on
for either endoscopic, or in some instances, surgical excision. </span></div>
</div>
மாங்குளம் AVM.பாஸ்கரன் M.Techhttp://www.blogger.com/profile/14275260072192866587noreply@blogger.com0tag:blogger.com,1999:blog-965294933794967194.post-63305410020850156882017-10-16T07:33:00.000-07:002017-10-16T07:33:03.848-07:00Screening algorithm<div dir="ltr" style="text-align: left;" trbidi="on">
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"> Sample and test numbers </span></b><br />
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></b>
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Few studies have examined the number of stool specimens necessary to optimise the diagnostic performance of FOBT. Consideration should be given to using more than one specimen together with criteria for assigning positivity which together provide a referral rate that is clinically, logistically and financially appropriate to the screening programme. The clinical sensitivity and specificity of testing can be modified depending on how the test data are used. Guaiac-based tests typically use 3 stools, but an algorithm using additional tests can be used to adjust clinical sensitivity and specificity</span><br />
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span>
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;">Determining test positivity </span></b><br />
<span style="font-family: Times, Times New Roman, serif; font-size: large;">The choice of a cut-off concentration to be used in an immunochemical test to discriminate between a positive and negative result will depend on the test device chosen, the number of samples used and the algorithm adopted to integrate the individual test results. Whilst an increasing number of studies are reporting the experience of different algorithms, local conditions, including the effect on sample stability of transport conditions, preclude a simple prescribed algorithm at this time. Adoption of a test device and the selection of a cut-off concentration should follow a local pilot study to ensure that the chosen test, test algorithm and transport arrangements work together to provide a positivity rate that is clinically, logistically and financially acceptable</span><br />
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span>
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;">QUALITY ASSURANCE IN ENDOSCOPY</span></b><br />
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></b>
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;">Guiding principles for a colorectal screening endoscopy service </span></b><br />
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></b>
<span style="font-family: Times, Times New Roman, serif; font-size: large;">1. People undergoing endoscopy, whether for primary screening, for assessment of abnormalities detected in screening, for assessment of symptoms, or for surveillance, should have as good an experience as possible, permitting them to encourage screening, assessment and surveillance of appropriate quality to their friends, family and colleagues. </span><br />
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span>
<span style="font-family: Times, Times New Roman, serif; font-size: large;">2. The provision of the service must take into account the perspectives of endoscopists and public health to ensure that the experience is high-quality, safe, efficient as well as person-oriented. </span><br />
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span>
<span style="font-family: Times, Times New Roman, serif; font-size: large;">3. Provision of screening should take account of historic development within different local and cultural contexts. </span><br />
<a name='more'></a><br />
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span>
<span style="font-family: Times, Times New Roman, serif; font-size: large;">4. The provision of primary screening endoscopy is less complex than follow-up endoscopy (of screen-positives) primarily because of the lower frequency of high-risk lesions in primary screening endoscopy. </span><br />
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span>
<span style="font-family: Times, Times New Roman, serif; font-size: large;">5. The introduction of screening must not compromise endoscopy services for symptomatic patients. </span><br />
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span>
<span style="font-family: Times, Times New Roman, serif; font-size: large;">6. Screening and</span><br />
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span>
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> symptomatic (diagnostic) services should achieve the same minimum levels of quality and safety. </span><br />
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span>
<span style="font-family: Times, Times New Roman, serif; font-size: large;">7. Wherever possible the quality assurance required for screening should have an enhancing effect on the quality of endoscopy performed for symptomatic patients and for other reasons. </span><br />
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span>
<span style="font-family: Times, Times New Roman, serif; font-size: large;">8. Screening and diagnosis of appropriate quality requires a multidisciplinary approach to diagnosis and management of lesions detected during endoscopy. </span></div>
</div>
மாங்குளம் AVM.பாஸ்கரன் M.Techhttp://www.blogger.com/profile/14275260072192866587noreply@blogger.com0tag:blogger.com,1999:blog-965294933794967194.post-84506174187890784282017-10-10T07:33:00.002-07:002017-10-10T07:33:31.627-07:00Sequential testing <div dir="ltr" style="text-align: left;" trbidi="on">
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Two consecutive diagnostic accuracy studies conducted in Scotland as part of the UK pilot screening
study investigated whether testing individuals with positive gFOBT tests using an iFOBT could be more
effective in selecting those who should receive colonoscopy (Fraser et al. 2006; Fraser et al. 2007) In
both studies the two-tier approach gave very high sensitivities of 95–96% with a negative carrying a
less than 1% chance of invasive cancer. The odds ratio for iFOBT positive subjects of having cancer
was 7.75 (95% CI 1.84–31.4). </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">A Chinese study (Li et al. 2006) of 324 subjects who had colonoscopy (mean age 53.5±15.3) showed
that an iFOBT following a positive gFOBT had a better specificity for colon cancer detection than
gFOBT (94.2% vs. 75.5%), and with similar sensitivity (93.8% and 95.9% vs. 95.9%, p>0.05). </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">In a multicentre comparison using different FOBT tests on 554 patients referred for colonoscopy
(mean age 59.8±11.7), a combination test with a highly sensitive gFOBT (Hemoccult SENSA) and an
iFOBT (FlexSure-FS or Hemeselect-HS, Beckman Coulter Inc. Fullerton, CA, USA) showed slightly
reduced sensitivity but significantly fewer false-positive tests than any single test (Greenberg et al.
2000). The specificity of SENSA/FS (95.7%, p=0.03) and SENSA/HS (95.2%, p=0.07) for the
detection of colorectal cancer were each greater than that of any individual test. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;">Participation rate and choice of test </span></b></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Factors that influence participation rate (uptake) are addressed in Chapter 2 (Sect. 2.4, 2.5.1.1 and
2.5.1.2). Whilst many studies have reported the effect on compliance of different test devices and
sampling permutations, some of these are contradictory and many reflect local circumstances. Whilst
the analytical methodology, gFOBT vs. iFOBT, will not directly influence compliance, the influence of
test methodology on the method of sampling, the number of samples required, a requirement for
dietary restriction and the improved clinical outcome will all have a bearing on uptake. The magnitude
of the influence will depend on local circumstances. Well-conducted randomised trials have clearly
demonstrated that better compliance can be achieved using current iFOBTs than with gFOBTs, but the
major influencing factor(s) remain a matter of speculation. In his recent paper Grazzini makes the
important observation that, in a biennial screening programme looking for a slow growing adenoma,
greater compliance over the long term might be more important than a higher detection rate on a
single screen (Grazzini et al. 2009).</span></div>
<br />
</div>
மாங்குளம் AVM.பாஸ்கரன் M.Techhttp://www.blogger.com/profile/14275260072192866587noreply@blogger.com0tag:blogger.com,1999:blog-965294933794967194.post-74717563313485772142017-10-04T01:58:00.000-07:002017-10-04T01:58:02.352-07:00Number of stool specimens <div dir="ltr" style="text-align: left;" trbidi="on">
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Several studies have now examined the influence of the number of samples used for testing on clinical
sensitivity and specificity. Allison takes any positive result from 3 stool samples measured using
FlexSure OBT as an indication for referral and shows higher sensitivity for cancer than studies using single stool samples (Allison et al. 2007). Unsurprisingly other studies show agreement with that
conclusion (St John et al. 1993; Allison et al. 1996; Knaani & Samuel 1997; Nakama et al. 1999;
Greenberg et al. 2000; Nakama, Zhang & Fattah 2000; Rozen, Wong et al. 2003). Nakama et al. using
Monohaem, showed sensitivities of 89% for cancer with 3 stools compared with 56% for a single stool
(Nakama et al. 1999).</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Using Hem-SP, Morikawa showed low sensitivity for cancer using a single-day sample (Morikawa et al.
2005). Rozen et al. (2006) used 3 stools for the OC-Sensor which contrasts with 2-day samples used
in Japan (Nakama, Zhang & Fattah 2000) and 1-day biennial testing performed in Italy (Castiglione et
al. 2002). The relative insensitivity in the Italian study to lesions in the proximal bowel (16.3 vs
30.7%) raises further doubts about the use of a single-day sample. In a study using OC-Sensor in an
at-risk population, Levi et al. (2007) took numeric measurements from three samples and used the
highest concentration of the three as the discriminating factor. Recent studies have taken the average
concentration from 2 stool measurements as the discriminating parameter, an approach that reduces
the positivity rate. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">The use of different cut-off limits and different numbers of stool samples illustrates how programme
algorithms can manipulate clinical sensitivities and specificities for the lesions of interest. Chen
describes the use of a cost-effectiveness model as a method of determining the optimal cut-off
concentration for an iFOBT (Chen et al. 2007). In the study by Levi et al. (2007) using an iFOBT OCMicro,
a scatter plot of 2 consecutive samples showed that of those with cancer or adenomas, 21 of
91 had elevated or markedly elevated faecal blood in one sample but were normal in the other. This is
further evidence of intermittent or variable bleeding, sample heterogeneity or poor sample technique
that will reduce clinical sensitivity. Imperiale (2007) commenting on the paper by Levi in his editorial
in Annals of Internal Medicine (Levi et al. 2007), speculated that concentration-related clinical
sensitivity and specificity could be used to determine post-test risk. If risk was related to subject age
or sex, this would provide more sophisticated criteria for colonoscopy referral than is currently used. </span></div>
<a name='more'></a><br />
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Guittet et al. (2009b), using a cut-off concentration of 20 ng/mL, reviewed the relative effectiveness
of using one sample, one positive from two samples, two positives from two samples or a mean
positive from two samples all measured using the Magstream iFOBT. The study concluded that for any
sensitivity the mean of two results provided the highest specificity, and at any positivity it provided
the highest sensitivity and specificity. It also concluded that one positive from a single specimen was
better than one from two specimens and the cut-off should be adjusted to provide an acceptable
positivity rate. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">A recent paper by Grazzini et al. (2009) looks at the clinical outcome of biennial population screening
in 20 596 residents of Northern and Central Italy aged 50–69 years. The study uses OC-Sensor and
compares outcomes from strategies using different cut-off limits (80, 100 and 120 ng/mL), one or two
samples and referral criteria based on either one positive or two positive results. No strategy is singled
out as preferable, although some show limited benefit. Generally, those strategies resulting in more
colonoscopy referrals increase the detection rate, particularly for adenomas, decrease the positive
predictive value and cost more. At the annual Digestive Diseases Week conference in 2010 van Roon
et al. (2010) illustrated the relationship between positivity rate, detection rate, cut-off limits, the
number of samples measured and the use of different algorithms for combining the results. For
positivity rates between 4% and 9% the user can obtain similar clinical outcomes by changing the cutoff
with either one or two samples. The dilemma for a population-screening programme is where to
draw the line between detection rates, cost and the inconvenience and morbidity associated with
colonoscopy. The study showed no significant reduction in uptake for the two-sample strategy, but it
did require the samples to be stored in a refrigerator. The choice is likely to be influenced greatly by
both financial and logistical considerations. </span></div>
</div>
மாங்குளம் AVM.பாஸ்கரன் M.Techhttp://www.blogger.com/profile/14275260072192866587noreply@blogger.com0tag:blogger.com,1999:blog-965294933794967194.post-54582399919753345112017-09-28T01:56:00.000-07:002017-09-28T01:56:00.183-07:00Optimising clinical performance using test cut-off limits & algorithms <div dir="ltr" style="text-align: left;" trbidi="on">
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;">Cut-off limits </span></b></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Until recently it has not been possible to adjust the analytical sensitivity of FOBT tests. This is still not
possible for existing gFOBTs, with the exception of the simple adjunct of hydrating the specimen prior
to testing with Hemoccult SENSA. With Hemoccult SENSA, hydration increases test sensitivity at the
expense of specificity, thereby increasing the false positive rate (Mandel et al. 1993; Ransohoff &
Sandler 2002). Hemoccult and Hemoccult SENSA have been compared in two large studies (Mandel et
al. 1993). As a result of rehydration, the rate of positive results increased more than fourfold, from
2.4 to 9.8%. Sensitivity increased from 80.8% to 92.2% while both specificity and PPV decreased
(specificity: 90.4% rehydrated and 97.7% non-rehydrated. PPV: 2.2 rehydrated and 5.6 non-rehydrated).
In the study by Levin, Hess & Johnson (1997) the positivity rates were 5% and 14.6% and PPV
14% and 7% respectively for the non-rehydrated and the rehydrated. Rehydration using Hemoccult
SENSA increases clinical sensitivity and decreases specificity and positive predictive value. The high
positivity rate of this approach renders it unsuitable for population screening.</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">With iFOBTs that provide a numeric result, it is possible to adjust the cut-off limit to obtain an acceptable
compromise between clinical sensitivity and specificity. This manipulation can provide an adequate
detection rate from an acceptable cohort of subjects invited for colonoscopy. Several recent
papers have addressed the issue of modifying the faecal haemoglobin cut-off limit of iFOBTs including
the following studies (Sieg et al. 1999; Castiglione et al. 2000; Nakama, Zhang & Zhang 2001;
Castiglione et al. 2002; Launoy et al. 2005; Vilkin et al. 2005; Rozen et al. 2006; Chen et al. 2007; van
Rossum et al. 2009). The data are summarised in Table 4.5. By increasing the positive cut-off limit,
the test sensitivity and positivity rate decreases and specificity and positive predictive values for
colorectal cancer detection increase. It must be appreciated that these studies used different
commercial products with different analytical characteristics, and therefore simple comparisons can be
misleading. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Chen found an analytical cut-off limit range of 100–150 ng/mL faecal haemoglobin in an iFOBT to
provide an acceptable balance between sensitivity and specificity (Nakama, Zhang & Zhang 2001;
Chen et al. 2007). Increasing the cut-off limit to 300 ng/mL brought an increase in specificity that was
small for the corresponding decrease in sensitivity and detection of cancers. A recent study by Rossum
of 6157 50–75 year old Dutch participants and using a single OC-Sensor collection and OC-Micro
analyser concluded that dropping from the standard 100 ng/mL cut-off to 75 ng/mL brought ‘optimal’
results and may be recommended for population screening in the Netherlands (van Rossum et al.
2009). This study also concluded that where colonoscopy capacity is insufficient, a cut-off up to 200
ng/mL would result in minimal false negatives for cancer although more for advanced adenoma. Policy
makers are faced with an arbitrary decision based on the balance between missed cancers/advanced
adenomas and the cost of colonoscopy </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<br /></div>
</div>
மாங்குளம் AVM.பாஸ்கரன் M.Techhttp://www.blogger.com/profile/14275260072192866587noreply@blogger.com0tag:blogger.com,1999:blog-965294933794967194.post-35929092347979518502017-09-23T01:55:00.000-07:002017-09-23T01:55:09.713-07:00European guidelines for quality assurance in colorectal cancer screening and diagnosis<div dir="ltr" style="text-align: left;" trbidi="on">
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;">Comparative clinical performance - gFOBT and iFOBT</span></b></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">In the USA, Allison et al. (2007) prospectively compared two types of FOBTs, a sensitive gFOBT
(Hemoccult SENSA) and a manual iFOBT (Flexsure). A large number of patients (7394 subjects were
eligible for the study) were requested to perform both tests. All patients positive for either FOBTs
were invited to have a total colonoscopy, whereas all patients negative to FOBT were advised to have
a sigmoidoscopy. All cancers occurring during the two years following the test were identified, so that
it was possible to estimate the absolute sensitivity and specificity for detecting advanced neoplasms in
the left colon within two years after the FOBT screening for the two tests administered separately and
in combination. The sensitivity for detecting cancer was 81.8% (95% CI = 47.8% to 96.8%) for the
iFOBT and 64.3% (95% CI = 35.6% to 86.0%) for the gFOBT. The sensitivity for detecting distal
advanced adenomas was higher for gFOBT than for iFOBT 41.3% (95% CI = 32.7% to 50.4%) vs
29.5% (95% CI = 21.4% to 38.9%). PPV was much higher for iFOBT than for gFOBT for distal cancer
(5.2% and 1.5% for iFOBT and gFOBT respectively) and for advanced adenomas (19.1 and 8.9% for
iFOBT and gFOBT respectively). The authors concluded that iFOBT has high sensitivity and specificity
for detecting left-sided colorectal cancer and that it may be a useful replacement for the gFOBT.</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">The study by Dancourt et al. (2008) compared the performance of a 3-day gFOBT and 2-day iFOBT in
17 215 subjects. For 1205 subjects who participated and had colonoscopy, the PPV for the guaiac and
immunochemical test was respectively 5.9% v 5.2% for cancer and 27.2% and 17.5% for adenoma. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">The study by van Rossum et al. (2008) represents a milestone in the comparison of gFOBT with
iFOBT, being the first randomised trial in a population based screening setting. A large number of
people (20 623) aged 50–75 years were randomised to either gFOBT (Hemoccult II, Beckman Coulter
Inc. Fullerton, CA, USA) or iFOBT (OC-Sensor). For iFOBT, the standard cut-off of 100 ng/mL was
used. iFOBTs showed higher compliance than did gFOBTs (56.9% vs 46.9% respectively p<.01). The
positivity rate was significantly higher in iFOBTs compared to gFOBTs (5.0% vs. 2.4% respectively,
p<0.01). Cancer or advanced adenomas were found, respectively, in 11 and 46 of gFOBTs and in 24
and 121 of iFOBTs. The detection rate per 1000 examinations for cancer was 71% higher in iFOBT
compared to gFOBT; the detection rate per 1000 examinations for advanced adenomas was 106%
higher in iFOBT as compared to gFOBT. The number-to-scope to find 1 cancer or 1 adenoma was
comparable between the tests, with the PPV not statistically different. In conclusion, iFOBT compared
to gFOBT demonstrated a higher detection rate with a similar PPV.</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">The results of these five studies are consistent with data from the first European screening programmes.
The UK Pilot study adopted Hema-screen, a conventional non-rehydrating gFOBT, using
duplicate samples on 3 consecutive stools extended to 2 further sets of 3 stools if indicated. This UK
pilot study gave a positivity rate during the first round of 1.9%. The Detection Rates (DR) for cancer
and neoplasia (cancer and advanced or non-advanced adenoma) were 1.62 in 1000 and 6.91 in 1000
respectively. The PPV for neoplasia was 46.9% in England and 47.3% in Scotland (UK Colorectal
Cancer Screening Pilot Group 2004). </span></div>
<a name='more'></a><br />
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">In Italy, a 1-day single sample iFOBT biennial test with positivity cut-off at 100 ng/mL is used in the
regional colorectal cancer programmes. The paper by Zorzi that described Italian screening
programmes showed a quite different outcome to the UK Pilot study (Zorzi et al. 2008). The positivity
rate was relatively high, 5.3% during the first round, the DR for cancer was 3.1 in 1000 (almost two
times the UK figure) and the DR for adenoma was 24.7 in 1000 (more than three times the UK result).
The PPV for neoplasia was slightly higher than that observed in UK pilot study (54% vs 46.9%) (UK
Colorectal Cancer Screening Pilot Group 2004). The Italian programme had adopted a more sensitive
(but less specific) strategy compared to the UK. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Hol et al. (2009) recently reported a randomised comparison of gFOBT (Hemoccult II) and iFOBT (OCSensor)
in a population-based trial in the southwest Netherlands (age 50–74 years). For gFOBT, any 1
of 6 windows collected from 3 stools was designated positive and for iFOBT a single result above a
cut-off concentration of 50 ng/mL was designated positive. Test kits were all distributed and returned
by mail. Participants with positive results received colonoscopy. gFOBT positivity was 2.8%, and iFOBT
positivity was 8.1% at a cut-off of 50 ng/mL, 5.7% at 75 ng/mL, 4.8% at 100 ng/mL and 4.0% at 150 ng/mL. At an iFOBT cut-off concentration of 75 ng/mL, the detection rate for advanced neoplasia was
2x higher than that by gFOBT and was considered to be the optimum cut-off and balance between
detection rate and positivity.</span> </div>
</div>
மாங்குளம் AVM.பாஸ்கரன் M.Techhttp://www.blogger.com/profile/14275260072192866587noreply@blogger.com0tag:blogger.com,1999:blog-965294933794967194.post-4172049043676348322017-09-18T01:52:00.000-07:002017-09-18T01:52:10.094-07:00Comparative clinical performance - gFOBT and iFOBT <div dir="ltr" style="text-align: left;" trbidi="on">
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Many studies comparing iFOBT and gFOBT have been performed in the last 8 years, and several
systematic reviews of the literature have been undertaken more recently. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">In 2007 Kerr published a systematic review by the Health Technology Assessment (NZHTA) of New
Zealand which had the aim of identifying the international evidence for the clinical and cost effecttiveness
of screening tests for colorectal cancer (Kerr et al. 2007). This review included all primary
research published as full original reports and secondary research, systematic reviews and meta-analyses published since November 2004. It also included seven eligible primary research papers
(Rozen, Knaani & Samuel 1997; Rozen, Knaani & Samuel 2000; Saito et al. 2000; Zappa et al. 2001;
Cheng et al. 2002; Cole et al. 2003; Ko, Dominitz & Nguyen 2003) and five eligible secondary research
papers; Australian Health Technology Advisory Committee (AHTAC) (1997), Conseil d'Évaluation des
Technologies de la Santé du Quebec (2000), Canada, Craven UK (Craven 2001), Young World Health
Organization and World Organization for Digestive Endoscopy (Young et al. 2002), Piper Blue Cross
Blue Shield Association Technology Evaluation Center US </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">The review concluded that “there is limited definitive evidence regarding superior immunochemical
FOBT performance over the guaiac tests. However, evidence from cross-sectional studies suggests
that the immunochemical test HemeSelect, Beckman Coulter Inc. Fullerton, CA, USA… is comparable,
or superior, to guaiac testing… The conclusions on this topic should be revisited if further reliable
evidence on the comparative performance of screening FOBTs becomes available”.</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">A similar conclusion was reached in a systematic review commissioned by the UK NHS and undertaken
by the Centre for Reviews and Dissemination of the University of York in 2007 (Burch et al. 2007)
which examined the literature until 2004. The review included 59 studies 39 evaluated gFOBTs, 35
evaluated iFOBTs and one evaluated sequential FOBTs. It concluded that there was no clear evidence
from direct or indirect comparisons to suggest that guaiac or immunochemical FOBTs performed better.
However amongst iFOBTs, Immudia-HemSP (now Hem-SP) appeared to be the most sensitive and
specific. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">In the four years since 2004, six studies comparing the performance of gFOBT and iFOBT have been
published (Levi et al. 2006; Smith et al. 2006; Allison et al. 2007; Guittet et al. 2007; Dancourt et al.
2008; van Rossum et al. 2008). Some further studies have investigated the accuracy of iFOBTs which,
although without a direct comparison with gFOBTs, confirmed the performance of iFOBTs which was
reported in the following studies </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">In Australia, Smith et al. (2006) performed a paired comparison of an iFOBT (InSure) with a sensitive
gFOBT (Hemoccult SENSA); 2351 asymptomatic and 161 symptomatic subjects were requested to
perform both FOBTs. iFOBT returned a true-positive result significantly more often in cancer (n = 24;
87.5% vs. 54.2%) and in significant adenomas (n = 61; 42.6% vs. 23.0%) while the false-positive
rate for any neoplasia was marginally higher with the iFOBT than the gFOBT (3.4% vs. 2.5%; 95% CI
of difference, 0–1.8%): the PPV for cancer and significant adenomas was slightly better for iFOBT
(41.9% vs 40.4%). </span></div>
<a name='more'></a><br />
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">In Israel, Levi et al. (2006) compared, a gFOBT with an iFOBT (OC-MICRO, now OC-Sensor) in a small
number (151) of patients referred for colonoscopy either because of a positive gFOBT or because they
were above average risk of colorectal cancer. Sensitivity, specificity, and positive predictive value for
significant colorectal neoplasia were 75%, 34% and 12%, respectively, for gFOBT, and were 75%,
94% and 60% for iFOBT. For a positive gFOBT, 4 times more colonoscopies were needed to identify a
significant neoplasm compared with iFOBT, and at more than 4 times greater cost. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">In France, Guittet et al. (2007) compared the performance of gFOBT and iFOBT (Immudia-HemSP
(now Hem-SP)) among 10 673 average-risk persons aged 50–74 years. Colonoscopy was offered only
if either FOBT was positive. The threshold for a positive iFOBT was varied between 20 ng/mL and 75
ng/mL. Overall, the results depended on the adopted iFOBT threshold. At the lower threshold (20
ng/mL), iFOBT detected 1.5 times as many cancers and nearly 2.6 times as many high-risk adenomas
as gFOBT; however, it also increased the relative false-positive rates (2.17 times more frequent for
each relevant lesion detected in iFOBT as compared to gFOBT). It is worth noting that at a threshold
of 75 ng/mL, iFOBT detected 90% more advanced neoplasms with a significant 33% decrease in the
false-positive risk. A further publication from this study (Guittet et al. 2009a) reported that the gain in
sensitivity from using iFOBT vis gFOBT was proportional to the degree of blood loss from the lesion
and its location. The benefits for cancer detection were restricted to lesion of the rectum. </span></div>
</div>
மாங்குளம் AVM.பாஸ்கரன் M.Techhttp://www.blogger.com/profile/14275260072192866587noreply@blogger.com0tag:blogger.com,1999:blog-965294933794967194.post-88784989003846468382017-09-13T01:51:00.000-07:002017-09-13T01:51:04.450-07:00Description of terms used to describe test effectiveness <div dir="ltr" style="text-align: left;" trbidi="on">
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Where, a are true positive, b are false positive, c are false negative and d are true negative</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Sensitivity = a/(a+c) </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Specificity = d/(b+d) </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">PPV = a/(a+b) </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">“True” in true positive, is an abstract concept because in practice a reference standard must be adopted.
For colorectal cancer screening, true is usually defined by the outcome of total colonoscopy, the
best practical diagnostic procedure we have though it does not have a sensitivity of 100%. In a clinical
setting it is not always possible to perform a total colonoscopy on all subjects who have negative
screening tests, so it is difficult to estimate the number of false negatives (c) and true negatives (d).
The difficulty of estimating false negative has a great impact on sensitivity but much less so on specificity.
In fact (c) is a number much lower than (d), so that the sum c+d (i.e. the number of negatives
to the test) is a small overestimate of d.</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">For sensitivity, (c) is a significant proportion of (a+c), so that it is necessary to have a direct estimate
of the number of false negatives. Very often this estimate is obtained by measurement of the interval
cancers (i.e. the number of colorectal cancers that are diagnosed in subjects negative to the test during
defined interval of time). Clearly the reliability of the estimated number of false negatives will
depend on the time interval, and that will increase as time elapses. It is therefore important when
comparing estimates of sensitivity obtained in this way to verify that the time interval used is the
same.</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">The ideal theoretical approach to estimating cancer-screening performance would be to obtain the
disease status using a “gold-standard” method that is independent of the screening method. For colorectal
cancer, the disease status is usually determined from a histological examination of biopsy specimens
of those with positive test results, because it is not ethically acceptable to collect biopsies from
all individuals undertaking a screening test. The sensitivity and specificity of screening test are therefore
usually estimated using interval cancers. As initially described by Day (1985) interval cancers will
not include slow-growing cancers missed by the test and not evident between two screening events
(therefore clinical sensitivity will be overestimated). Conversely, interval cancers will include fastgrowing
cancers not present at the time of the screening test, but developing during the interval
period (thus underestimating clinical sensitivity). This limitation is common to all screening procedure
evaluations. </span></div>
<a name='more'></a><br />
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> Programme sensitivity is an estimate of sensitivity (i.e. the number of CRC detected/the number of
cancers detected plus the number of interval cancers occurring in a certain interval of time) and is
biased toward overdiagnosis of CRC (i.e. it estimates diagnosis of CRC that would never occur
clinically). For this reason it is sometime preferable to give an estimate of sensitivity based on the
ratio between interval cancers (in a defined time period) and the number of cancers expected in the
same period (more precisely, 1- (interval cancers occurred in x years/expected cancers in x years)).
This estimate gives an idea of cancers anticipated by screening, and it is not affected by overdiagnosis.
</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">It is also worth noting that from a practical point of view, the choice of the test (or combination of
tests) is not based on clinical sensitivity and specificity but on the determination of detection rate (for
cancer or adenomas) and its correlation with positivity being first correlated to sensitivity and latter to
specificity. </span></div>
</div>
மாங்குளம் AVM.பாஸ்கரன் M.Techhttp://www.blogger.com/profile/14275260072192866587noreply@blogger.com0tag:blogger.com,1999:blog-965294933794967194.post-52275498053241560642017-09-08T01:48:00.000-07:002017-09-08T01:48:07.368-07:00Clinical performance <div dir="ltr" style="text-align: left;" trbidi="on">
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;">Description of terms used to describe test effectiveness </span></b></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">gFOBT screening has been proven to be effective in reducing colorectal cancer mortality (Hewitson et
al. 2007). In randomised trials the reduction in cause-specific mortality ranged from 15% (Hardcastle
et al. 1996) to 33% (Mandel et al. 1993). Such a large variance in mortality can be explained by test
differences, different numbers of faecal samples, different intervals between invitation cycles (one-year or two-year) and different responses to invitation associated with the characteristics and composition
of the population screened. The sensitivity and specificity quoted for a test will therefore be
influenced both by the test’s analytical characteristics and the context in which the test is used and
evaluated. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">gFOBTs come in two forms, the conventional form with normal sensitivity and the more sensitive
variety, Hemoccult SENSA, in which the sample is hydrated before analysis. Hemoccult SENSA performs
quite differently from the gFOBTs used in European trials (Hardcastle et al. 1996; Kronborg et
al. 1996) and is both more sensitive and less specific. Comparison of the clinical performance of
gFOBT and iFOBT is complex because iFOBTs can have different levels of specificity and sensitivity
indeed they may have variable positive cut-off concentrations. Changes in cut-off concentrations
result in different clinical performance characteristics.</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Although only one population-based RCT has been described with iFOBT (van Rossum et al. 2008),
the many published diagnostic accuracy studies provide information on the comparative ability of current
tests to distinguish subjects with or without colorectal cancer and adenoma and can be considered
an acceptable indication of the satisfactory performance of iFOBT in population screening (Burch et
al. 2007). </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"></span></div>
<a name='more'></a><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span><br />
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Diagnostic accuracy studies have compared: </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">a) subjects performing one or both tests (gFOBT and iFOBT) and performing a total colonoscopy (or
sigmoidoscopy) independently from the result of the test (cohort studies);</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> b) subjects performing one or both tests and undergoing colonoscopy if one or both tests are positive
(cohort studies); </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">c) Diagnosis determined beforehand and the test performed subsequently (case-control studies);
and </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">d) Different subjects performing different tests </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Colorectal cancer, large adenomas ( 10 mm), high-risk adenomas (high-grade dysplasia, villous
change, serrated histology or 3 polyps), all adenomas (including small adenomas), alone or combined
have been used as reference standards in the various studies.</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">The comparative clinical performance of the different tests has usually been based on the following
indicators: Sensitivity, specificity, Positive Predictive Value (PPV), false positive rate, likelihood ratio for
a positive or a negative test which is derived from sensitivity and specificity (sensitivity/(1-specificity))
for + LR; (1-sensitivity)/specificity for –LR. </span></div>
</div>
மாங்குளம் AVM.பாஸ்கரன் M.Techhttp://www.blogger.com/profile/14275260072192866587noreply@blogger.com0tag:blogger.com,1999:blog-965294933794967194.post-55042888860454988312017-09-03T23:36:00.000-07:002017-09-03T23:36:00.200-07:00Quality Assurance<div dir="ltr" style="text-align: left;" trbidi="on">
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"> Quality assurance of gFOBT testing </span></b></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Whilst an immunochemical test is recommended, programmes that adopt a traditional guaiac
test need to apply additional laboratory quality procedures. To minimise variability and error
associated with visual test reading, including manual results input, the following procedures
should be considered</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">o Use of appropriate temperature for artificial lighting and neutral-coloured walls in the
reading laboratory; </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">o Use of a national laboratory training programme to prosper consistency of interpretation; </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">o A blinded internal QC check each day for each analyst prior to commencing testing;</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">o Adoption of a monitoring programme to identify operator related analytical performance
(e.g. positivity variability and bias); and </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">o Double entry of test results </span></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></b></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"> Quality assurance of iFOBT testing </span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Consistency in analytical performance must be assured by the adoption and application of rigorous
quality assurance procedures. Manufacturer’s Instructions for Use must be followed. Laboratories
should perform daily checks of analytical accuracy and precision across the measurement
range with particular emphasis at the selected cut-off limit. Rigorous procedures need to
be agreed and adopted on how internal quality control data is interpreted and how the laboratory
responds to unsatisfactory results. Performance data, both internal quality control and
external quality assessment data, should be shared and reviewed by a Quality Assurance team
working across the programme. Sufficient instrumentation should be available to avoid delays in
analysis due to instrument failure or maintenance procedures</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"> External quality assessment </span></b></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">A European external quality assessment scheme should be developed to facilitate Europe-wide
quality assurance of occult blood testing and enhance the reproducibility of testing within and
between countries providing population screening</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"> Outcome monitoring </span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">All aspects of laboratory performance in respect of the screening test should be part of a rigorous
quality assurance system. Uptake, undelivered mail, time from collection to analysis, analytical
performance (internal QC and external QA), positivity rates, lost & spoilt kits and technical
failure rate, technician performance variability and bias should each be subject to rigorous
monitoring</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;">Quality of information </span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> The proportion of unacceptable tests received for measurement is influenced by the ease of use
of the test kit and the quality of the instructions for use. This proportion should not exceed 3%
of all kits received; less than 1% is desirable </span></div>
</div>
மாங்குளம் AVM.பாஸ்கரன் M.Techhttp://www.blogger.com/profile/14275260072192866587noreply@blogger.com0tag:blogger.com,1999:blog-965294933794967194.post-77045474351435314822017-08-28T23:33:00.000-07:002017-08-28T23:33:00.889-07:00Faecal sampling/collection system <div dir="ltr" style="text-align: left;" trbidi="on">
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Many factors influence the uptake and reliability of sample collection. Inappropriate implementation
can result in grossly misleading results. No single collection methodology is supported by
the literature; however, the following factors should be considered when selecting a device for
taking samples in population screening:</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> The distribution process should be reliable and reach all selected subjects.</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> The laboratory should be able to unambiguously identify the subject ID on the test device
perhaps using a suitable barcode. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> The laboratory should be able to check the manufacturer’s device expiry date on each returned
device. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> The instructions for using the device must be simple and clear. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> The device should to be simple and easy to use by the target population. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> The device should leave minimal opportunity for collection error. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> The device should facilitate consistency in the volume of sample collected. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> The device/instructions should discourage inappropriate repeat sampling into/onto the sample
device.
Misuse of the device by participants should not cause loss of sample buffer.</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> The system should not be susceptible to interference from toilet bowl disinfectants, etc.</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> The screening participant should be able to record the date of sample collection to ensure
the laboratory can verify receipt within an acceptable sample stability period. </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> The process used by the subject for returning the device should be simple, reliable, safe
and, when appropriate, should meet EU postal regulations.</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> A local pilot study should be undertaken to ensure that the chosen device and associated distribution,
sampling and labelling procedures are acceptable </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;">Laboratory organisation</span></b></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"> Number of laboratory sites</span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> Population screening necessitates the receipt, measurement and recording of thousands of tests
each day. The samples should be analysed without delay to avoid further sample denaturation
and avoid an increase in false negative results. Inter-laboratory analytical imprecision is well described
and can be observed through established external quality assurance schemes. Improved
consistency is achieved by adopting common analytical platforms, analytical and quality standards
and shared staff training. The analysis needs to be reproducible across a screening population
and therefore the number of analytical centres should be minimised with automated
analytical systems utilised wherever possible and agreed common testing procedures adopted
by each centre </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;">Laboratory staff </span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> All laboratories providing population screening should be led by a qualified clinical chemist who
is trained and experienced in the techniques used for analysis and with clinical quality assurance
procedures </span></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></b></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"> Laboratory accreditation and quality monitoring </span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> All laboratories providing screening services should be associated with a laboratory accredited to
ISO 15189:2007 Medical laboratories - Particular requirements for quality and competence. The
laboratories should perform Internal Quality Control (IQC) procedures and participate in an
appropriate External Quality Assessment Scheme (EQAS) </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"> Distribution of FOBT kits by mail </span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> Distribution and receipt of FOBT kits using local postal services can be an effective means of
reaching the designated population </span></div>
</div>
மாங்குளம் AVM.பாஸ்கரன் M.Techhttp://www.blogger.com/profile/14275260072192866587noreply@blogger.com0tag:blogger.com,1999:blog-965294933794967194.post-30645729472105859742017-08-22T23:31:00.000-07:002017-08-22T23:31:06.482-07:00Screening algorithm<div dir="ltr" style="text-align: left;" trbidi="on">
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"> Sample and test numbers </span></b></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Few studies have examined the number of stool specimens necessary to optimise the diagnostic
performance of FOBT. Consideration should be given to using more than one specimen together
with criteria for assigning positivity which together provide a referral rate that is clinically,
logistically and financially appropriate to the screening programme. The clinical sensitivity and
specificity of testing can be modified depending on how the test data are used. Guaiac-based
tests typically use 3 stools, but an algorithm using additional tests can be used to adjust clinical
sensitivity and specificity</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;">Determining test positivity</span></b></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">The choice of a cut-off concentration to be used in an immunochemical test to discriminate
between a positive and negative result will depend on the test device chosen, the number of
samples used and the algorithm adopted to integrate the individual test results. Whilst an increasing
number of studies are reporting the experience of different algorithms, local conditions,
including the effect on sample stability of transport conditions, preclude a simple prescribed
algorithm at this time. Adoption of a test device and the selection of a cut-off concentration
should follow a local pilot study to ensure that the chosen test, test algorithm and transport
arrangements work together to provide a positivity rate that is clinically, logistically and financially
acceptable</span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;">Test interference: </span></b></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></b></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"> Dietary restriction </span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> Dietary constituents present potential interference in guaiac faecal occult blood tests. Dietary
restriction has not been demonstrated to significantly increase screening specificity, and risks
reducing participation rate. The potential for dietary interference is significantly less for immunochemical
tests. With the qualification that a diet peculiar to a particular country or culture
may not have been tested or reported, dietary restriction is not indicated for programmes using
either guaiac-based or immunochemical tests </span></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></b></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"> Drug restriction </span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> Interference from bleeding associated with drugs such as aspirin, nonsteroidal anti-inflammatory
drugs and anticoagulants (e.g. warfarin) present potential interference in both guaiac and
immunochemical faecal occult blood tests. Although the literature carries some contradicting
reports of the effect of anticoagulants on screening outcome, drug restriction is not recommended
for population screening programmes using either guaiac-based or immunochemical
tests </span></div>
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மாங்குளம் AVM.பாஸ்கரன் M.Techhttp://www.blogger.com/profile/14275260072192866587noreply@blogger.com0tag:blogger.com,1999:blog-965294933794967194.post-10547526480012175912017-08-16T23:27:00.000-07:002017-08-16T23:27:00.161-07:00FAECAL OCCULT BLOOD TESTING<div dir="ltr" style="text-align: left;" trbidi="on">
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<b><span style="font-family: Times, Times New Roman, serif; font-size: large;">Guaiac-based faecal occult blood tests </span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"> Guaiac-based faecal occult blood tests have proven characteristics that make them suitable for
population screening. They lack the analytical specificity and sensitivity of immunochemical
tests, their analysis cannot be automated and the concentration at which they turn from negative
to positive cannot be adjusted by the user. For these reasons guaiac-based tests are not
the preferred test for a modern population screening programme, although depending on local
labour costs, the mechanism of kit distribution and collection and reduced sample stability in
immunochemical testing, they might prove more practicable and affordable than immunochemical
testing </span></div>
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<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
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<b><span style="font-family: Times, Times New Roman, serif; font-size: large;">Immunochemical faecal occult blood tests</span></b></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Immunochemical tests have improved test characteristics compared to conventional guaiac-based
tests. They are analytically and clinically more sensitive and specific, their measurement can
be automated and the user can adjust the concentration at which a positive result is reported.
Immunochemical tests are currently the test of choice for population screening; however, individual
device characteristics including, ease of use by the participant and laboratory, suitability
for transport, sampling reproducibility and sample stability are all important when selecting the
iFOBT most appropriate for an individual screening programme</span></div>
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<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
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<b><span style="font-family: Times, Times New Roman, serif; font-size: large;">DNA and other related new markers </span></b></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Only tests for blood in faeces have been demonstrated to have the necessary characteristics to
be suitable for population screening. DNA and other related new markers are currently
unsuitable for screening, either singly or as members of a panel of tests</span></div>
<div style="text-align: justify;">
<b><span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></b></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;"><b>Sample stability between collection and analysis</b> </span></div>
<div style="text-align: justify;">
<span style="font-family: Times, Times New Roman, serif; font-size: large;">Whilst a maximum period of 14 days between collection and analysis is quoted for many guaiac
faecal occult blood tests, that quoted for immunochemical tests is significantly shorter. Until
more stability data are published, screening programmes should adopt the conditions and
period of storage described in manufacturer’s Instructions for Use having determined that they
are appropriate for local conditions which might expose samples to high temperatures for long
periods of time</span></div>
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<span style="font-family: Times, Times New Roman, serif; font-size: large;"><br /></span></div>
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மாங்குளம் AVM.பாஸ்கரன் M.Techhttp://www.blogger.com/profile/14275260072192866587noreply@blogger.com0