Risks

Risks and limitations of the fecal occult blood test include:

• The test isn't always accurate. Your fecal occult blood test could show a negative test result when cancer is present (false-negative result) if your cancer or polyps don't bleed.

  Your test could show a positive result when you have no cancer (false-positive result) if you have bleeding from other sources, such as a stomach ulcer, hemorrhoid, or even blood swallowed from your mouth or your nose.

• Having a fecal occult blood test may lead to additional testing. If your fecal occult blood test result is positive, your doctor may recommend a test to examine the inside of your colon, such as a colonoscopy.