Faecal Immunochemical Test
Note: this site is for informational purposes only. To view test results or book a test, use the NHS app in England or contact your GP.
A faecal immunochemical test (FIT) analyses a stool (faecal) sample to detect tiny amounts of human blood that may not be visible. It is used to screen for or investigate bleeding from the bowel, which can be a sign of bowel cancer or other intestinal conditions.
Why get tested?
To screen for bleeding from the gut/intestine and investigate symptoms suggestive, 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 also used for patients presenting to their GP with symptoms suggestive of bowel cancer (NICE guideline DG56 and NG12). Patients will usually be asked to complete a FIT test before being referred for other investigations such as colonoscopy.
Sample required?
One sample of faeces collected into a special container.
You collect a sample yourself, in the privacy of your own bathroom, using a special kit. The actual collection method varies between manufacturers. Read all the instructions very carefully before starting to collect your sample.
Test preparation needed?
For the FIT test, there are no dietary, drug, or dental procedure restrictions. However, avoid collecting samples during a menstrual period. The test uses antibodies to detect only human blood from the lower digestive tract (colon).
For all tests, follow the instructions that are provided by the doctor or included in the test kit.
Common questions
The main use for the FIT test is to screen and investigate for bowel cancer. Blood in the stool may be the only symptom of early cancer. If the cancer is detected before it metastasises (spreads to other areas), there is a greater chance it can be treated successfully. A positive FIT test does not necessarily ‘prove’ that you have cancer. There are other possible causes of bleeding and other follow-up procedures will need to be done to find the source of the bleeding.
Faecal immunochemical (FIT) tests may be done as part of a range if investigations if your doctor suspects that your symptoms suggest that you may have cancer. This test is also used as a screening tool for early detection of bowel cancer. The FIT test is used in the National Bowel Cancer Screening Programme. This programme offers screening every two years to all men and women aged 54 to 74 in England who are registered with a GP, (51 to 74 years in Wales,60 to 74 years in Northern Ireland and 50 to 74 in Scotland). People within the age range are automatically sent an invitation and test kit. The programme in England is gradually expanding to make it available to everyone aged 50 to 53 years. People aged over 74 can opt in to screening.
Please review your results in line with the cut-off in use within your local laboratory. In a patient with symptoms, a result of greater than or equal to 10 ug/g faeces is a positive result (NICE NG12). A positive result indicates blood in the stool and further investigation is required to identify the source of the bleeding.
Before or after you have a FIT test, you may have a rectal examination. A positive FIT test may be followed by imaging tests to determine the source of the blood:
- Sigmoidoscopy: an examination of the rectum and lower colon (part of the intestines) with a lighted instrument to look for abnormalities, such as polyps
- Colonoscopy: a more thorough examination of the rectum and entire colon
- CT colonography: uses computed tomography (CT) scans to check the large bowel (colon) and back passage (rectum). It’s also called a virtual colonoscopy
The devices available to buy detect blood in faeces using several different methods. Their sensitivity to detecting blood can vary and without the skills of either an experienced laboratory or doctor the results of these tests can be misleading. Consult your GP if you are concerned and think you need a test performed.