A new study has found that direct-to-consumer genetic tests, like those marketed by 23andMe, Ancestry.com, Family Tree DNA, and MyHeritage, can be used to obtain innacurate results.
Data dump: Most of these tests use a technique called genotyping to provide information about a person’s ancestry, risk of developing certain disorders, or status as a carrier of specific diseases. Some companies also make the raw genotyping data available to customers upon request.
Lost in interpretation: Scientists at Ambry Genetics, a diagnostics company that also interprets data from consumer DNA tests, looked at this raw genotyping data from 49 people. They found that two out of five reported genetic variants, or 40 percent, were false positives—that is, they indicated that a particular genetic variant was present when it wasn’t. Most of the false-positive calls were of cancer-linked genes.