Immunochemical faecal occult blood testing (FOBT) works “exceptionally well” to rule out the need for colonoscopy in primary care patients with low-risk bowel cancer symptoms, UK researchers have found.

They showed in a large population study that triage of such patients using FOBT had a negative predictive value (NPV) of 99.8% and a positive predictive value (PPV) of 7%.

The diagnostic performance of FOBT was evaluated in a project involving all patients in Southwest England with symptoms considered low-risk — but compatible with colorectal cancer (CRC) — being sent home from their GP with the stool test kit that detects haemoglobin.

The patients were older than 50 with unexplained abdominal pain or weight loss, 50-60 years with a change in bowel habit or iron deficiency anaemia, or over 60 with anaemia regardless of iron deficiency.