There’s a downside to genetic testing
These days, you can have your blood sampled, your cheek swabbed or your saliva analyzed to find out whether you’re predisposed to Alzheimer’s disease, various forms of cancer, lactose intolerance, restless leg syndrome — even baldness.
Some 1,200 tests can diagnose thousands of health conditions, compared with about 100 tests a decade ago.
You’ll pay anywhere from $150 to thousands of dollars per procedure.
Some tests are administered only by medical professionals.
Others are available to anyone with a credit card on Web sites like Navigenics or www.decodeme.com . To paraphrase a recent New England Journal of Medicine article: The genome is definitely out of the bottle.
These new genetic tests are intriguing, but how can you tell whether they’re worth the financial (let alone emotional) expense?
Could an adverse result cost you your job?
Your health insurance? No one would begrudge a breakthrough that can help people understand their risk of disease, or help them prevent or manage it.
But the old adage “buyer beware” definitely applies.
For starters, there are few guarantees that the tests are analytically valid (that is, they can be relied upon to get the right answer) or clinically valid (they actually relate to a person’s health or risk of disease).
“There is no good way for consumers or physicians to be sure of the quality of genetic tests,” said Gail Javitt, law and policy director of the Genetics and Public Policy Center of Johns Hopkins University in Baltimore. “That applies to those sold directly to consumers or administered by doctors.”
One way to better your odds of getting reliable results is to use only those labs that are certified under Clinical Laboratory Improvement Amendments, or CLIA, standards.
Even if you assume the tests are accurate, some have questionable utility. Few are 100 percent predictive, so a positive result may not mean that you’ll develop a disease, nor does a negative result guarantee your immunity.
Most diseases are caused by a combination of genes, lifestyle and environment that’s not well understood.
Nor can most tests say when a disease will strike or how severe it will be.
With any test, you should get a clear explanation, preferably from a genetic counselor, about how the data correlates with any suggested condition. That advice goes double if the tester is marketing a remedy — say, dietary supplements.
In May, President Bush signed into law a bill pushed by Rep. Louise
M. Slaughter, D-Fairport, that forbids employers and insurance companies from denying employment, promotions or health coverage to people when genetic tests show they have a predisposition to cancer, heart disease or other ailments.
Despite the legislation, designed to counter fears of participating in clinical trials, some fear genetic discrimination might remain a threat.
So for now, it makes sense to approach these tests with a grain of salt — and to share the results at your own risk.
