In colon cancer prevention, the detection of haemoglobin in stool samples can be used as useful marker for gastrointestinal bleeding. Colorectal Adenomas and Tumours are a source of intermittent blood in stool which when detected in symptomatic or asymptomatic individuals is an indication for colonoscopy to locate the source of bleeding.
In combination with colonoscopy, a specific immunoassay for haemoglobin in stools is proven to be able to reduce the risk of mortality due to colon cancer. The advantages of immunological assays that detect and quantify human haemoglobin over guaiac-based tests are numerous, and include benefits related to sensitivity and specificity.
In addition, it is not necessary for the patient to follow a special diet prior to the test as unlike Guaiac tests immunological (FIT) tests donot suffer interference from raw meat, radish, or foods containing vitamin C.
Quantitative Faecal Immunochemical Tests (FIT) for the detection of haemoglobin in stool have recently been evaluated by NICE to help physicians select and refer patients in Primary Care with suspected colorectal cancer. In addition, recent studies have demonstrated that FIT tests are useful for excluding a multitude of lower gastrointestinal organic pathologies (e.g. colorectal cancer, IBD etc) with a high negative predictive value in symptomatic patients in Primary Care settings.