Panorama general
A fecal immunochemical test (FIT) looks for tiny amounts of blood in a stool sample. FIT can find blood that can't be seen just by looking at the stool. FIT is an option for colon cancer screening in people who don't have any symptoms.
FIT is one type of a fecal occult blood test (FOBT). The medical term for hidden blood is occult blood. Occult blood in the stool may be a sign of cancer or polyps in the colon or rectum. Polyps are growths of cells that aren't cancerous but could become cancerous over time. Adenomas and serrated lesions are two types of polyps that could become cancerous.
If a fecal immunochemical test finds blood in your stool sample, you likely need a colonoscopy to find the source of the bleeding.
Don't have FIT if you have symptoms of colon cancer. These symptoms may include blood in the stool or in the toilet. Other symptoms include pain in your abdomen, a change in bowel habits, unexplained weight loss or a blood clot in the lung.
Also don't use FIT if you have a high risk of colon cancer. This includes if you have a history of colon polyps or if a close family member has had colon cancer. A colonoscopy is the preferred test. During colonoscopy, a healthcare professional looks at the inside of the colon and rectum and may remove lesions or polyps.
Talk with your healthcare team about your symptoms and health history if you are considering colon cancer screening.
Por qué se hace
A colon cancer screen is a test that checks for signs of cancer before symptoms happen. A screening test has two goals. The first is to find and remove polyps before they turn into cancer. The second is to find cancer early when it can be treated more easily.
A fecal immunochemical test uses antibodies to find tiny amounts of hemoglobin in your stool. Hemoglobin is a protein in your blood. FIT looks for blood from your lower digestive tract.
FIT is a simple test that requires no bowel preparation. Some people prefer this test over the other screening tests because it can be done at home. It doesn't require missing work for a medical appointment. Other people may choose this test because it often is less expensive than other tests.
FIT is one of several colon cancer screening tests available. Talk with your healthcare professional about which tests might be right for you. Insurance providers typically pay for screening tests. Talk with your insurance provider to confirm what your plan covers.
Colon or rectal cancer is commonly called colorectal cancer. Sometimes, FIT is known as an iFOBT.
Riesgos
The test isn't always accurate
A fecal immunochemical test looks for hidden blood. If no blood is found, the test result is negative. But sometimes the test can be wrong. This is called a false-negative. It can happen if you have cancer or polyps that don't bleed. Or if there is blood that the test doesn't find. That's why healthcare professionals recommend the test be done every year.
If blood is found, the test result is positive. But bleeding can be caused by something other than cancer or polyps. This is called a false-positive. The blood could come from a stomach ulcer or a hemorrhoid. It even could be swallowed from your mouth or nose.
The test may lead to more testing
The fecal immunochemical test is an acceptable test for a person who has an average risk of colorectal cancer because of its ability to find cancer and adenomas. The test is proved to lower the chance of dying of colorectal cancer.
If blood is found in your fecal immunochemical test, a healthcare professional may recommend a different test to find the source of the bleeding. The most common follow-up test is a colonoscopy.
Cómo prepararte
You don't need to prepare for the fecal immunochemical test. Unlike other fecal occult blood tests, you don't need to change when you eat or drink and you don't need to stop taking your medicines before you collect a stool sample.
Qué esperar
You take the fecal immunochemical test at home. You may receive a kit from your healthcare professional. Or your health professional may arrange to have the kit sent to you or to your pharmacy.
The kit typically includes everything you need to complete the test, including instructions. You collect a stool sample from one bowel movement. The test kit may include a stick or brush that you use to collect the sample. You place the sample in a container that comes with the test kit. Then you return the container to a lab for testing, often by mail. Send it within 24 hours.
Kits also are sold without a prescription. Some kits instruct you to send your sample to a lab. Other kits give the results in a few minutes. It's important to report your results to your healthcare professional.
If your kit is missing instructions or individual parts, tell the healthcare professional who gave or mailed the test to you.
Resultados
Your healthcare professional receives the results of the fecal immunochemical test and then shares the results with you. Results may include:
- Negative result. A FIT is negative if no blood is found in your stool. If you have an average risk of colon cancer, your healthcare professional may recommend repeating the test every year.
- Positive result. A FIT is positive if blood is found in your stool. Your healthcare professional may recommend a colonoscopy to find the source of the bleeding.
Nov. 14, 2025