Faecal immunochemical tests (FIT) in low-risk symptomatic populations

Quantitative faecal immunochemical tests (FIT) to guide referral for colorectal cancer in primary care

Offer testing for occult blood in faeces to assess for colorectal cancer in adults without rectal bleeding and have low-risk symptoms suggestive of colorectal cancer, but do not meet the criteria for a suspected cancer pathway. This low-risk symptomatic population has a low probability (0.1%-3%) of colorectal cancer:

≥50y + unexplained weight loss OR abdominal pain

<60y + any change in their bowel habit or iron-deficiency anaemia

≥60y + anaemia without iron deficiency

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Symptomatic FIT test threshold is set lower than asymptomatic screening FIT test threshold

The threshold of abnormality for asymptomatic screening programme patients is set moderately-low (120ug Hb/g faeces).  So if someone has a negative screening test, and doubt remains, they must be encouraged to undergo a symptomatic FIT test kit which uses a very-low (<10ug Hb/g faeces) threshold and may therefore identify a positive faecal occult blood result.

Patient is referred for colonoscopy (or CT colonography) if either screening FIT test or low-risk symptomatic FIT test is abnormal.