Home-use faecal immunochemical testing: primary care diagnostic technology update.

Abstract

#### Clinical Question What is the evidence base for home faecal immunochemical testing for colorectal cancer? A variety of home-use faecal occult blood testing (FOBt) kits remain commercially available to UK patients despite caution regarding their safety and accuracy. FOBt is a relatively non-invasive and inexpensive test. The NHS Bowel Cancer Screening Programme (BCSP) and the majority of European screening programmes uses guaiac FOBt (gFOB). A Cochrane Review has shown that biennial population screening with card-based postal laboratory-analysed gFOB can reduce colorectal mortality by 15% (relative risk [RR] 0.85, confidence interval [CI] = 0.78 to 0.92) in people aged 45–74 years.1 Those who attend screening have a 25% reduction (RR 0.75, CI = 0.66 to 0.84) in their risk of death, but only 40% return all three BCSP gFOB kits, although involving GPs in screening increases uptake.1,2 Faecal immunochemical testing (FIT) measures the globin component of human haemoglobin. Unlike gFOB, FIT does not require dietary restriction, is specific to lower gastrointestinal (GI) cancers as upper GI enzymes degrade human globin, and is less affected by concomitant medication use. FIT has started to replace gFOB in some regions (for example, the Czech Republic and Italy) and guidelines (for example, the US) given these gains in diagnostic accuracy. Home FIT kits are designed to obtain samples from multiple parts of a single stool and use immunochromatography to provide an immediate (qualitative) positive or negative result, avoiding the delay and costs associated with laboratory (quantitative) FIT and gFOB. Patients may present to primary care having used home bowel-testing kits, and so this report outlines the existing evidence detailing the potential accuracy and utility of the home FIT available to the adult consumer. Based on a search conducted in December 2013, Box 1 shows the CE approved FIT kits retailing to the UK …