To perform the test, a small stool sample is collected at home using special cards or cloths. These are then returned to the surgery or laboratory, where the samples are checked for traces of blood not visible to the naked eye.

FOBTs use chemical reactions to detect haem, a component of the haemoglobin in red blood cells. There are a few different types including guaiac and immunochemical tests, with varying sensitivity and specificity.

Results are reported as positive or negative for blood. While not diagnostic, a positive FOBT warrants follow up with a colonoscopy or other procedures to investigate the source of bleeding.

Faecal occult blood tests are considered an important preventative screening tool. When performed regularly as recommended, FOBTs can help detect colorectal cancer early when treatment is most effective. Speak to your GP about whether this simple test may be right for you.