Home DNA Tests: Buyer Beware
Can a home DNA test reveal your future health? WebMD investigates.
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
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.