The Faecal Immunochemical Test (FIT) uses antibodies that specifically recognise human haemoglobin (Hb). It means that a FIT result is not influenced by the presence of other blood in stools, such as that ingested through diet, compared to the guaiac Faecal Occult Blood Test (gFOBT), therefore reducing the chance of false positive results.
It is used to detect and can quantify the amount of human blood in a single stool sample. A positive FIT result suggests that there may be bleeding within the gastrointestinal tract that requires further investigation. Those with a positive result are then invited for further testing, normally colonoscopy.
The FIT test has replace the Faecal Occult Blood test (FOB test) for bowel cancer screening.