Nearly half of home genetic tests could be wrong, study says

Curious about your ancestry? At-home DNA tests are popular, but nearly half of them could be wrong, according to a new report.

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Researchers from AmbryGenetics, a medical laboratory in California, recently conducted a study, published in the Nature journal, to determine the accuracy of genetic testing companies, including 23andMe.

To do so, they assessed 49 people who completed “direct-to-consumer” DNA tests and sent the results to third parties for analysis. These companies link a person’s examination to published research on their genes and predict potential medical implications. The 23andMe direct-to-consumer genetic test is the only one authorized by the FDA to offer reports on genetic risk.

The scientists then checked those analyses with a more detailed genetic test from clinical labs and found that only 60 percent of the tests could be confirmed.

"This is extremely concerning," Cecelia Bellcross, director of genetic counseling training program at Emory University, told The Atlanta Journal-Constitution. "The challenge is we have the ability to look at thousands of genetic mutations but not interpret them. You have an 1000 piece puzzle and you're trying to predict what it is with 10 pieces."

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Bellcross, who wasn’t a part of the study, also noted that false positives can cause anxiety and possibly encourage patients to take unnecessary action.

“If individuals are told they have this high risk mutation in the BRCA1 gene, which can increase a woman’s chances of developing breast or ovarian cancer, it could lead to that person having their breast and ovaries removed,” she said. “They may also share with their family members who may go down the same path.”

For those who purchase at-home DNA tests, she encourages them to set up an appointment with a genetic professional to be repeat the testing. She also recommends seeking out organizations, such as the National Society of Genetic Counselors, that offer genetic counseling online or over the phone.

“Without consultation, it could lead to serious harm,” Bellcross said. “People need to be careful. Don’t take at face value what you’re getting in terms of those results.”

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