The market for direct-to-consumer (DTC) genetic tests is booming—with companies such as AncestryDNA, 23andMe and MyHeritage blanketing media with ads for the at-home tests to uncover information about ancestry or genetic mutations and variants that could lead to health problems.
A recent small-sample survey published online March 22 in Genetics in Medicine found these tests may produce false-positives in 40 percent of variants when subjected to clinical confirmation testing.
“[This study] emphasizes the limitations in raw genotyping data currently distributed by DTC companies and demonstrates the importance of confirming DTC raw data results in a diagnostic laboratory that is well versed in clinical-grade variant detection and classification,” wrote lead author Stephany Tandy-Connor, MS, with Ambry Genetics, and coauthors. “While having access to raw genotyping data can be informative and empowering for patients, this type of information can also be inaccurate and misinterpreted. Genetic testing needs to be interpreted by a qualified healthcare professional in the context of several other factors, such as personal and family medical history.”
Most DTC tests are not intended as diagnostic tools, though the FDA approved one tester, 23andMe, to offer a test for 10 specific conditions, including Parkinson’s, Alzheimer’s, and celiac disease. But clinical diagnostic testing offers more complete and more accurate testing for specific genetic conditions.
In this study, the researchers examined 49 cases from individuals who agreed to share DTC genetic testing results with medical providers. Follow-up testing was then conducted on all participants.
The team found a false-positive rate of 40 percent—with errors including misinterpretation or misclassification from the DTC companies and third-party interpretation services.
“[A]ll parties involved with these types of test results should be aware that many DTC genetic tests do not include comprehensive gene analysis, and an individual may still need additional clinical diagnostic genetic testing based on personal and/or family history,” wrote Tandy-Connor et al. “It is important that consumers and their health-care providers are cognizant of the differences in testing methodologies between clinical diagnostic labs and DTC testing labs so that there is no false reassurance or alarm on the behalf of the individual or the healthcare provider.”
Nicholas joined TriMed in 2016 as the managing editor of the Chicago office. After receiving his master’s from Roosevelt University, he worked in various writing/editing roles for magazines ranging in topic from billiards to metallurgy. Currently on Chicago’s north side, Nicholas keeps busy by running, reading and talking to his two cats.