Ask a Doctor: How effective are at-home colon cancer tests?

Medical doctor with a stethoscope around his neck holding
photo Dr. Colleen Schmitt, Galen Digestive Health; member, Chattanooga-Hamilton County Medical Society

Q: I've seen ads for at-home colon cancer tests that don't require a colonoscopy. How effective are these tests?

A: These types of tests use stool samples to look at your DNA to see if it's altered by precancerous or cancerous cells. As part of its normal process, our bodies shed DNA in our colons all the time, and the DNA is passed into the stool. The problem with this type of testing is it detects cancer but does not perform as well in detecting precancerous cells from a polyp. Remember that at-home DNA stool tests are only for those who have no family history of colon cancer, no personal history of polyps and no symptoms.