Stool DNA test

The stool DNA test is a noninvasive laboratory test that identifies DNA changes in the cells of a stool sample. The stool DNA test specifically looks for DNA alterations associated with colon polyps and colon cancer.

The major goal of the stool DNA test is to detect whether DNA changes that indicate colon cancer or precancerous polyps are present in the colon.

One stool DNA test (Cologuard) is approved for use the United States.

Why it's done Risks How you prepare What you can expect Results

Stool DNA testing is intended to screen healthy people with no symptoms for colon cancer or precancerous polyps. The test also measures blood in the stool. Research shows the stool DNA test is effective at detecting colon cancer and precancerous polyps.

How stool DNA testing works

The stool DNA test detects signature DNA changes in tumor cells that are found in the stool.

Because the lining of the colon is always shedding cells, including cells from the surface of polyps and cancers, these markers are available in the stool. A stool DNA test can identify several of these markers, indicating the presence of precancerous polyps or colon cancer.

Many different DNA changes may be present in colon cancer cells, so the stool DNA test looks for a panel of DNA markers. Also, because DNA markers may be present in only tiny amounts in stool, very sensitive laboratory methods are required.

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