With direct-to-consumer genetic tests becoming increasingly popular, physicians should expect questions from their patients about those results.
Patients will likely look to their doctors and other clinicians for guidance when they get test results from companies such as 23andMe, one of the first to offer genetic testing to the general public, according to a scenario designed to educate physicians for this increasingly likely occurrence, which was published in the Annals of Internal Medicine.
Doctors need to know there are gaps in what these direct-to-consumer tests do and don’t tell patients, the study’s lead author Wendy K. Chung, M.D., Ph.D., a professor of Pediatrics and Medicine at Columbia University, said in an interview with Fierce Healthcare.
While these tests may be great for people who want to learn about their ancestry or who want to try and find long-lost relatives, they have their limits when it comes to medical use, Chung says.
It can get confusing when a patient uses a direct-to-consumer test to try and determine if they could pass along a hereditary condition to their offspring or if they carry the BRCA gene that is linked to breast and ovarian cancer. For instance, 23andMe only tests for three genetic mutations when it comes to BRCA testing, so for patients who are not of European or Ashkenazi Jewish descent, the test may not provide any useful information.
“There may be other tests that can be done to oftentimes address the question the patient was really asking,” Chung says.
These direct-to-consumer tests are also limited in that a patient’s risk for developing a disease is often modified by other interacting genes, environment, lifestyle and family history.
Doctors need to make patients aware of the limitations of these tests. The best bet is for clinicians to refer patients with genetic concerns to a genetic counselor or another qualified provider, the researchers said.
“The message is there’s probably a real, medical genetic test,” Chung said. That test can provide reliable diagnostic results for patients, as well as a follow-up so they have a correct interpretation of test results.
One potential drawback of direct-to-consumer genetic tests is that patients may develop a false sense of security and think something isn’t a problem based on the test results, she said.
A study led by researchers at Invitae found that 23andMe’s BRCA test missed almost 90% of mutation carriers, both in those with and without a personal or family history of cancer, according to the New York Times. The data, not yet published, was presented at the American College of Medical Genetics and Genomics annual meeting.