Faecal sampling/collection system

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:

The distribution process should be reliable and reach all selected subjects.

 The laboratory should be able to unambiguously identify the subject ID on the test device perhaps using a suitable barcode. 

 The laboratory should be able to check the manufacturer’s device expiry date on each returned device. 

 The instructions for using the device must be simple and clear. 

 The device should to be simple and easy to use by the target population. 

 The device should leave minimal opportunity for collection error. 

 The device should facilitate consistency in the volume of sample collected. 

 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.

 The system should not be susceptible to interference from toilet bowl disinfectants, etc.

 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.  

 The process used by the subject for returning the device should be simple, reliable, safe and, when appropriate, should meet EU postal regulations.

A local pilot study should be undertaken to ensure that the chosen device and associated distribution, sampling and labelling procedures are acceptable   

Laboratory organisation

 Number of laboratory sites

  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

Laboratory staff 

 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 

 Laboratory accreditation and quality monitoring 

 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) 

 Distribution of FOBT kits by mail 

 Distribution and receipt of FOBT kits using local postal services can be an effective means of reaching the designated population