Measurement of faecal haemoglobin with a faecal immunochemical test can assist in defining which patients attending primary care with rectal bleeding require urgent referral.

Patients with rectal bleeding and f-Hb <10 μg Hb/g faeces are unlikely to have SBD and could be investigated by sigmoidoscopy alone. Using the faecal immunochemical test to guide investigation of patients with rectal bleeding is a rational and practical way forward.