The fecal immunochemical test, often shortened to FIT, is used to determine the presence of occult blood in the stool. Occult or hidden blood in the stool can indicate precancerous polyps or colon cancer, explains the Colon Cancer Alliance.
The blood vessels located on the surface of benign or cancerous intestinal tumors are often delicate and easily injured by passing stool. These blood vessels usually release tiny amounts of blood into the stool. A FIT can detect blood in the stool that is invisible to the naked eye, states Colon Cancer Alliance.
The FIT is done in basically the same way as a traditional fecal occult blood test, explains Colon Cancer Alliance, but it tends to be more accurate as its results are not affected by intake of food or medicines. Another factor that increases the test's accuracy is that it usually only detects occult blood from the lower intestines. It rarely reacts to bleeding in the upper gastrointestinal tract.
The FIT is a newer type of screening test. It cannot diagnose colon cancer, explains MedlinePlus.com. Individuals who are at a higher risk for developing colon cancer, including those with a family history of colorectal cancer or a personal history of chronic inflammatory bowel disease, are advised to undergo colon cancer screening tests. The FIT is commonly performed with other screening examinations, such as a colonoscopy or sigmoidoscopy.