Home DNA Tests: Buyer Beware

Can a home DNA test reveal your future health? WebMD investigates.

Medically Reviewed by Michael W. Smith, MD on June 04, 2007
3 min read

Will you have heart disease one day? Diabetes? To find out, your doctor's office is a good place to start. He or she can gauge your risk by weighing your age, family history, and lifestyle choices.

Yet companies marketing home DNA test kits claim you can discover the secrets of your genetic makeup and the future of your health in the privacy of your own home.

You'll find home genetic tests online and lining your pharmacist's shelves. The tests vary in price, depending on what they look for: At $250, cystic fibrosis testing is relatively inexpensive, while ovarian cancer testing can cost more than $3,000. In addition to revealing genetic "secrets," these tests also claim to identify paternity and genealogy.

How do they work? You swab your cheek for cells that are loaded with DNA, take a "no-mess" stool sample, or visit a lab for a blood test. You then mail the sample for analysis, and in less than a month, on average, your genetic health profile is returned, with information about your genetic background, an assessment of your risk, and recommendations for reducing your risk.

Is all this possible? "Human beings are 99.9% identical," says Joan Scott, MS, deputy director of the Genetics and Public Policy Center at Johns Hopkins University. "The 0.1% difference at the genetic level is what makes each of us unique."

By examining that 0.1% of your DNA, these companies look for clues in your genes, called variants, that might increase your risk of one day developing a disease, explains Scott. But do these tests pass scientific muster and provide valuable personal health knowledge? The jury is still out -- but some health experts are saying "Buyer, beware."

A recent report issued by the Senate Special Committee on Aging stated that these tests can be unreliable, misleading, and overly broad, with the results containing obvious recommendations -- for instance, "If you smoke, quit." The report also cited genetic testing experts who say links between gene mutations and most diseases are unproven.

Other national health organizations, such as the CDC the FDA, say that genetic tests should be done only on the advice of a doctor and in a lab setting -- not at home -- and that they are no substitute for regular face-to-face checkups. And the FDA, the regulatory agency responsible for reviewing genetic tests, has approved only 12 of the 1,000 currently available; of that dozen, none is the "at-home" version.

  • Make sure the company you select to analyze your DNA uses a lab certified by the Clinical Laboratory Improvement Amendment, which established quality standards for laboratory testing to ensure the accuracy, reliability, and timeliness of test results.
  • Ask your doctor to review and interpret your test results.
  • Be wary of home genetic testing companies that sell you a test, then push vitamins or other products as a way to help prevent disease.