1. Is the over-the-counter (OTC) at-home test just as good?
While the OTC tests that are dropped into the toilet are fairly sensitive, your doctor may prefer the gFOBT or one of the immunochemical FOBTs. Since the color change that is observed is subject to the interpretation of the observer, the tests sent to a professional laboratory may be more reliable. The staff are more experienced than most patients in interpreting the sometimes subtle color change and are more familiar with sources of false negative and false positive results.
2. What kind of procedures might follow a positive FOBT?
An FOBT may be preceded or followed by a digital rectal exam. A positive FOBT may be followed by:
Sigmoidoscopy: an examination of the rectum and lower colon with a lighted instrument to look for abnormalities, such as polyps;
Colonoscopy: a more thorough examination of the rectum and entire colon; and
3. Are there any other types of tests for colorectal cancer that are run on stool samples?
Yes. There is a stool DNA (sDNA) test available. The test can detect certain alterations to DNA in cancer cells shed into the stool. Studies have shown that the test has acceptable sensitivity, although it cannot identify all types of colorectal cancer. Guidelines released in March 2008 jointly by the American Cancer Society, the American College of Radiology, and the US Multi-Society Task Force on Colorectal Cancer added sDNA to their list of recommended testing options for colorectal cancer screening.
This article was last reviewed on March 30, 2008.
This page was last modified on April 8, 2009.
The review date indicates when the article was last reviewed from beginning to end to ensure that it reflects the most current science. A review may not require any modifications to the article, so the two dates may not always agree.
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