What are the benefits and limitations of the fecal tests?

The primary advantage of these tests is that collection of fecal samples for blood or DNA testing can be performed at home, without bowel preparation. Fecal occult blood tests are also inexpensive on a per test basis when compared to other screening methods. However, these tests are less likely to lead to cancer prevention compared with the invasive tests; they must be repeated at more frequent intervals to be effective; and if the test is positive, colonoscopy is required. Patients choosing to be screened with fecal tests should also be comfortable with a cancer detection program that will not prevent most colon cancers. It must also be recognized that some stool tests (particularly older versions of guiaic-based tests) do not detect the majority of cancers present at the time of testing, and should therefore not be used for colorectal cancer screening.

If patients are not willing to have annual testing or to have colonoscopy if the test is positive, or if available fecal tests have not been shown in the medical literature to achieve the recommended cancer detection threshold, fecal testing programs will not be effective and should not be recommended.