Genetic tests sold online or in stores may produce false results, warn genetics experts in the UK.
When one of these tests indicates a health risk, it doesn’t necessarily mean someone will develop the health problem, and conversely, reassuring results may be unreliable, they caution in the British Medical Journal (BMJ).
“We had several people coming to our clinic who appeared to have a genetic test result that put them at very high risk of developing a condition, for example, cancer,” said senior author Anneke Lucassen of the University of Southampton.
“When we checked their result with a more detailed technique, we found that it wasn’t there,” she told Reuters. Health. “We then realised that colleagues across the country were coming across similar examples.”
Although most manufacturers warn against making healthcare decisions based on the results of direct-to-consumer (DTC) tests, some people do, Lucassen added.
“I think people often expect any genetic test to be clear cut,” she said. “The marketing around DTC tests suggests people will find out about themselves and that results are accurate.”
Genetic tests often promise insights into ancestry, disease risks, personality or athletic ability, the authors write, but interpreting genetic information is complicated. Importantly, most direct-to-consumer tests don’t sequence the complete set of a person’s genes, or genome, and instead focus on specific variants in genes, which can lead to falsely positive results. Even tests that do sequence the full genome often identify variants that may not mean anything clinically, they point out.