Faecal immunochemical test (FIT)
What this test measures
The FIT detects tiny amounts of human blood in stool. It is the test used in the NHS bowel screening programme and, at a different threshold, by GPs for people with bowel symptoms.
Why doctors request it
Sent by post every two years in the screening programme, and requested by GPs for symptoms such as a change in bowel habit.
What commonly pushes it up
- Bleeding from anywhere in the bowel: haemorrhoids, polyps, inflammation or cancer
- Menstrual blood in the sample
- Some anti-inflammatory painkillers as a class
What commonly pushes it down
- A negative result is the usual finding
Everyday reasons for a value outside the range
- The screening programme threshold (120 ug/g in England, lower in Scotland) is much higher than the symptomatic threshold of 10 ug/g, so the same number means different things
- Haemorrhoids are a common benign cause
About the sample
A single small sample using the kit provided; no dietary preparation needed.
Upload a photo or PDF and see every line against the range your lab printed, explained in plain English. First report free.
Read my report freeThis is an educational summary of results you uploaded. It is not medical advice, a diagnosis or a treatment plan, and it does not replace the doctor who requested the test. If you are worried, or a result is marked outside range, discuss it with your doctor. Written and reviewed by a UK consultant physician. Reference ranges vary between laboratories.