A survey of external quality assessment schemes (EQAS) for faecal immunochemical tests for haemoglobin (FIT)

Immunochemical assays for faecal haemoglobin (FIT) are used in colorectal cancer (CRC) screening programmes and for patients with symptoms suggestive of CRC. External quality assessment schemes (EQAS) for FIT have been established, however although there are ISO standards for EQAS with the ideal aim of establishing Category 1 schemes, there are no criteria to guide schemes for FIT. The aim of this study was to gather information by survey from EQAS FIT programmes, to find out the current similarities and differences, and to work towards establishing what ideal FIT EQAS look like to assist EQA schemes to make improvements. 24 schemes were identified worldwide; 16 responded to the survey. Programmes cover different testing environments and different patient groups. The number of sample distributions per year ranged from 1-12; most schemes did not provide faecal-based samples (69%), and for those that do, they mostly did not indicate if samples were provided in the assay manufacturers' sample buffer (88%). 69% of respondents provided information on reporting units and 31% use the recommended reporting units (μg Hb/g faeces); several methods were described for assigning target values, performance criteria and reporting performance. This survey indicates that large differences exist between the current FIT EQA schemes.