Faecal Occult Blood Test and Faecal Immunochemical Test

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Also known as: FOB, FOBT, gFOBT, Hemoccult, iFOBT, FIT
Formal name: Faecal Occult Blood Test
Related tests: Full Blood Count, Calprotectin, Stool DNA

At a Glance

Why Get Tested?

To screen for bleeding from the gut/intestine, which may be an indicator of bowel cancer

When to Get Tested?

The test is used to screen for bowel cancer especially as part of the National Bowel Cancer Screening Programme. Outside of the Screening Programme the test is not widely available but it may sometimes be used when a patient has a family history of cancer of the intestine and some other organs, or to help diagnose long-term unexplained anaemia if imaging tests, such as colonoscopy, are unavailable. Patients with symptoms that are suspicious of gut cancer will usually be referred for imaging tests without having the FOB test first.

Sample Required?

One or more samples of faeces (stool)

Test Preparation Needed?

For the guiac-based FOB test (gFOBT), you may be instructed to avoid certain medications and follow certain dietary restrictions for several days before collecting the stool samples. For the immunochemical FOB test (iFOBT, FIT), there are no dietary or drug restrictions.