A fecal occult blood test (FOBT) looks at a sample of your stool (feces) to check for blood. Occult blood means that you can't see it with the naked eye. Blood in the stool means there is likely some kind of bleeding in the digestive tract. It may be caused by a variety of conditions, including:

• Polyps
• Hemorrhoids
• Diverticulosis
• Ulcers
• Colitis, a type of inflammatory bowel disease

Blood in the stool may also be a sign of colorectal cancer, a type of cancer that starts in the colon or rectum. Colorectal cancer is the second leading cause of cancer-related deaths in the United States and the third most common cancer in men and in women. A fecal occult blood test is a screening test that may help find colorectal cancer early, when treatment is most effective.

Other names: FOBT, stool occult blood, occult blood test, Hemoccult test, guaiac smear test, gFOBT, immunochemical FOBT, iFOBT; FIT

The National Cancer Institute recommends that people get regular screenings for colorectal cancer starting at age 50. The screening may be a fecal occult test, a colonoscopy, or another test. Talk with your health care provider about which test is right for you.

If you choose a fecal occult blood test, you need to get it every year. If you have a colonoscopy, you only need it every ten years. But it is a more invasive procedure. You may need screening more often if you have certain risk factors. These include:

• A family history of colorectal cancer
• Cigarette smoking
• Obesity
• Excessive alcohol use

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