Q. My doctor prescribed a Cologuard test instead of a colonoscopy. No one mentioned how often Cologuard could result in false positive test results, as mine did. So, a colonoscopy was necessary after all, but it turned out fine.

No polyps were detected.

How often does that happen?

A. We searched unsuccessfully for a simple answer to your straightforward question.

The company that makes Cologuard, a DNA stool test for colorectal cancer, suggests that the rate of false positives might be around 6%.

A study designed to assess Cologuard’s false positive rate reported that it was 37% (American Journal of Gastroenterology, Supplement, October 2023).

A more recent evaluation among about 3,000 patients yielded a positive test in 482 people (15%).

Of those, more than half had a follow-up colonoscopy, as you did (American Journal of Gastroenterology, April 8, 2025).

The colonoscopies revealed 10 actual colon cancers and 61 pre-cancerous lesions. That left 184 people who had false positive results from DNA testing in this study.

The authors conclude, “Together, these findings raise questions about the effectiveness of screening based on MT-sDNA (Cologuard) testing in

an average risk population.”

Q. A renowned senior cardiologist in our area has been taking all his patients off statins and putting them on Repatha. He did this for my husband, and the results have been amazing.

Within three months, his cholesterol was perfect.

All of his statin-related symptoms, from muscular aches to mental confusion, have disappeared. His LDL, which had been over 200, is in the 50s.

The physician feels that all statins have side effects — including to the brain — that Repatha does not have.

Each patient just has to secure their insurer’s approval. Because patient satisfaction and compliance with Repatha is so good, hopefully, insurers will see the benefit of this switch.

A. Thank you for sharing this perspective on evolocumab (Repatha). The Food and Drug Administration recently expanded the indications for this cholesterol-lowering medicine. It was previously just for patients with heart disease and high LDL cholesterol levels.

Starting on Aug. 25, doctors can prescribe it for anyone with elevated lipids.

Many people have difficulty with statins. Many readers of this column report muscle aches and pains, arthritis, weakness, cramps, blood sugar problems and cognitive complaints.

To learn about Repatha, statins and other ways to reduce the risk for heart disease, you may wish to read our “eGuide to Cholesterol Control and Heart Health.”

This online resource can be found under the Health eGuides tab at www.PeoplesPharmacy.com.

Q. I have suffered from dandruff for years and have at last come up with a solution. I rinse my scalp with old-fashioned amber Listerine about twice a week after shampooing.

On alternate days, I use Nizoral shampoo. This combination has solved the problem.

A. Once upon a time, the maker of Listerine promoted this mouthwash for “infectious dandruff.”

The FDA discouraged this use, and the company no longer recommends this approach.

That said, we have heard from many readers that Listerine can be helpful against dandruff or seborrheic dermatitis.

Both are linked to yeast overgrowth on the scalp.

Listerine, like Nizoral (ketoconazole), has antifungal activity that discourages yeast. Your combination seems like a highly effective strategy.

In their column, Joe and Teresa Graedon answer letters from readers. Write to them in care of King Features, 300 W. 57th Street, 41st Floor, New York, NY 10019, or email them via their website: www.PeoplesPharmacy.com. Their newest book is “Top Screwups Doctors Make and How to Avoid Them.”