This week, Newsweek reporter Mary Carmichael has been soliciting legal, academic and industry experts' advise in a quest to decide if she will take a direct-to-consumer genetic test. Yesterday, she asked the question: How reliable are at-home DNA tests?
Stanford law professor Hank Greely, JD, responded to her inquiry saying:
You can be confident you can’t trust the results, because there’s no consensus on interpretation, and personalized medicine isn’t just about genetics. If your test shows you have a genetically low risk of lung cancer but you smoke four packs a day, your actual risk is much higher than average. Besides, will a 3.4 percentage-point difference in risk change your life-or be worth paying good money for? (Oh, and if you aren’t of European ancestry, good luck getting any meaning out of these tests-the research behind the results was almost always done with white people.)
Knowledge can be powerful, both when understood properly and-dangerously-when misunderstood. If you test negative for [BRCA mutations that are linked to breast and ovarian cancer], you might decide to avoid mammograms. That could be fatal. Not having those mutations lowers your genetic risk only from about 12.5 percent to 12.4 percent. As a first step the FDA should require that every health-related genetic test be prescribed by, and be returned through, your doctor.
Carmichael makes her decision about taking the genetic test tomorrow. The entire series and Greely's full response are worth reading, especially if you're looking for a good primer on the debate over direct-to-consumer genetic tests.
Previously: Over-the-counter genetic tests are a bad idea, Stanford expert says
Photo by Marco Bellucci