NICE - quantitative faecal immunochemical tests (FIT) to guide referral for colorectal cancer in primary care

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Faecal immunochemical tests (FIT), a type of faecal occult blood test, are designed to detect small amounts of blood in stool samples using antibodies specific to human haemoglobin

  • been developed as an alternative to guaiacbased faecal occult blood tests, which involve using chemicals that react with the haem component of haemoglobin in the blood and produce a blue colour change if blood is detected.
    • sometimes, this colour change can happen because the chemicals react with food in a person's diet or with medicine that a person is taking; this can lead to false test results
  • faecal immunochemical tests are designed to specifically detect human haemoglobin, they may give more accurate test results than guaiac-based tests
    • target the globin component of haemoglobin, which degrades as it travels through the gastrointestinal tract, so these tests are less likely to detect globin from upper gastrointestinal bleeding.

NICE have stated that (1):

  • the OC Sensor, HM-JACKarc and FOB Gold quantitative faecal immunochemical tests are recommended for adoption in primary care to guide referral for suspected colorectal cancer in people without rectal bleeding who have unexplained symptoms but do not meet the criteria for a suspected cancer pathway referral outlined in NICE's guideline on suspected cancer
  • results should be reported using a threshold of 10 micrograms of haemoglobin per gram of faeces. Companies should provide advice about the performance characteristics of the assays to laboratories, and ensure standardisation of results

NICE urgent colorectal cancer guidance:

  • Refer people using a suspected cancer pathway referral (for an appointment within 2 weeks) for colorectal cancer if:
    • they are aged 40 or over
      • with unexplained weight loss and abdominal pain
    • or they are aged 50 or over
      • with unexplained rectal bleeding
    • or they are aged 60 or over with:
      • iron-deficiency anaemia or
      • changes in their bowel habit, or
    • tests show occult blood in their faeces (for who should be offered a test for occult blood in faeces see below)

  • a suspected cancer referral (for an appointment within 2 weeks) should also be considered for:
    • people with a rectal or abdominal mass
    • adults aged under 50 with rectal bleeding and any of the following unexplained symptoms or findings:
      • abdominal pain
      • change in bowel habit
      • weight loss
      • iron-deficiency anaemia.

NICE criteria for requesting test for occult blood in faeces (FIT):

  • should be offered to adults without rectal bleeding who:
    • are aged 50 or over with unexplained:
      • abdominal pain or weight loss
    • or are aged under 60 with:
      • changes in their bowel habit or
      • iron-deficiency anaemia
    • or are aged 60 or over and have anaemia without iron deficiency


Last reviewed 01/2022