Consumer Gene Tests: Help or Harm?
Experts, Test Makers Battle Over Selling Genetic Tests to Patients
Genetic Tests for Antidepressant Sensitivity continued...
"We don't say the test can't be helpful. We just say you can't tell, and
until you can tell, don't use it," Berg tells WebMD. "We are not saying
the manufacturers are making false claims. ... We were a little disappointed
that the evidence wasn't stronger than it was."
Coleman says the EGAPP standard is too high.
"That is the very most rigorous, very most conservative standard of
proof," he says. "It is certainly appropriate for new drugs, but not
for new genetic tests. These demands for clinical trials are over the top in
terms of the level of proof we need to use this testing. There is an asymmetry
between the level of benefit [from genetic testing] and this level of
Berg says EGAPP is skeptical of this "genetic exceptionalism"
suggesting that genetic tests are somehow different than other medical
"One of the things these companies don't emphasize is that you can
develop a plausible argument for how these genetic tests might work, but we are
also interested in the harmful effects," he says. "With all tests,
there are potential benefits and potential harms. We did not find evidence for
either one of those in CYP tests for SSRI sensitivity."
How Should Genetic Tests Be Used?
Javitt and colleagues worry that patients armed with genetic test results
will stop taking their medicines or change their doses without first consulting
Is it really so hard to understand the results of genetic tests? Yes, says
Jeffery M. Vance, MD, PhD, chairman of human genetics and genomic medicine at
the University of Miami.
"Direct-to-consumer testing is never something that should be condoned
and probably something that needs to be monitored," Vance tells WebMD.
"With genetic tests, like other medical tests, you really need someone who
can put it into context. That requires a physician. So it is the
direct-to-consumer testing that is really a big problem."
But Vance thinks people should get genetic tests and have that information
kept with their medical records.
"You could, for instance, get a CYP test and have your genotype known
early in life," he says. "So say you're a slow responder to some drugs.
Well, through your life there may be different drugs that come up where this is
important or not important. The information is very important, but only in
certain situations: It has value only in terms of the context in which it is
Vance predicts genetic testing will one day be routine and that doctors
certainly will use the information to individualize drug treatments.
Coleman, however, argues that patients themselves should control this
"There is concern about the privacy of this information -- and if you
don't trust the medical system to maintain the confidentiality of genetic
testing, you may not get it or get the benefit from it," he says. "It
is a bedrock right of patients to control this information about