FIT in Primary Care

Faecal Immunochemical Testing (FIT) is a stool test that is highly sensitive for identifying bleeding in the gastrointestinal tract, a sign of bowel cancer. FIT offers an improved method for identifying people with significant risk of bowel cancer who should be referred for investigation.

This replaces the guaiac based Faecal Occult Blood Test (gFOBt). This has no specificity for human haemoglobin, leading to false positives from dietary sources of haemoglobin and antioxidants or peroxidase activity from food and drugs. FIT (Faecal Immunochemical Test) uses antibodies that specifically recognise human haemoglobin so it is a much more sensitive and specific test of gastrointestinal bleeding than gFOBt.

In July 2018 the Transforming Cancer Services – Early Diagnosis team put together a business case or the use of FIT in patients with suspected bowel cancer symptoms and a risk of less than 3%. Read the FIT Business Case V12 Final.

Following the increased infection control demands on endoscopy during the COVID-19 pandemic, GPs across London are now asked to have patients return a FIT kit before referring to assess for bowel cancer in adults with abdominal and bowel symptoms (except for patients with unexplained rectal or anal masses). FIT allows rapid identification of people who need definitive testing via endoscopy, which should reduce delays following presentation to diagnosis. Compared to endoscopy FIT is a more convenient and accessible test with much less impact on daily activities. Find out more about how the referral pathway for lower GI referrals changed during the COVID-19 pandemic.


Safety Netting for patients on the FIT pathways is important to ensure appropriate follow-up and onward care. For the TCST top tips for Safety Netting please see our guide for GPs.

Patients with < 10 µg Hb/g faeces can now be managed in primary care through appropriate active follow up  and safety netting. Please follow the link below to find out more about the FIT admin pathway, including a poster for practices to download.