What is a Faecal Occult Blood Test?
The Faecal Occult Blood Test (often abbreviated to FOBT) is a test to detect blood in the stools/faeces that may not be obvious to the naked eye ('occult' in this context means 'hidden').
It is a straightforward test that can be completed at home - with a test kit you need to take two samples of your faeces (from two separate visits to the toilet on different days) - which are then sent away to a laboratory for testing.
Blood in faeces - even very small amounts - can be caused by bowel cancer or polyps (although cancers or polyps may be present without any bleeding). The FOBT will detect even very small amounts of blood.
What do the results mean?
The test will come back with either a negative or a positive result. This is what these results mean...
If there is no blood detected, you will receive a negative result. This does not necessarily mean that polyps or cancer are not present, since some polyps and cancers do not bleed.
If there is blood detected, you will receive a positive result. Again this is not conclusive evidence of the presence of cancer or polyps. Bleeding could be coming from other sources, such as a stomach ulcer, haemorrhoids, or in some cases, even blood from your nose or mouth you have swallowed.
A positive test will result in a recommendation of further examination, normally a colonoscopy to investigate the cause of the bleeding.
How often should I take an FOBT?
All people aged over 50 are recommended to take an FOBT every two years from that age (recommended by The Cancer Council Australia and the National Health and Medical Research Council), and people considered high risk - where there is a family history of bowel cancer or any other condition that increases the risk of bowel cancer - are advised to set up a screening schedule with their doctor.
How do I prepare to take the test?
If you see any bleeding or blood in the stool with the naked eye, do not take the test, instead arrange an appointment with your doctor.
Women should not take the test within 3 days of having a period.
You may need to avoid certain foods (eg broccoli, turnips, red meat, horseradish).
You may need to avoid certain medications (eg aspirin, ibuprofen, vitamin C).
The aim of the FOBT is to enable any serious bowel or gastrointestinal conditions to be detected early, which maximises the chances of prevention or cure. If you have a strong family history of bowel cancer, FOBT screening may not be suitable for you. Therefore, discuss bowel cancer screening with your primary care physician to select the best method suited for your individual circumstances.