NEW YORK — A working group is developing guidelines to help primary care providers handle the nuances and complexities of direct-to-consumer genetic testing results.
While many consumers seek DTC genetic testing to learn about their ancestry or certain traits, such tests increasingly provide clinically relevant data on carrier status, pharmacogenomic interactions, and risk of cancer or complex disease.
If consumers receive a result that concerns them, they are likely to consult with their primary care provider, Mylynda Massart, a family medicine physician at the University of Pittsburgh Medical Center, said during a session of the American College of Genetics and Genomics annual meeting on DTC genetic testing on Friday. Patients, she noted, likely can get an appointment sooner with a PCP than with a specialty genetics provider and may already have a relationship with the PCP. But PCPs might not be aware of all the intricacies of DTC genetic testing results, she said.
"Many non-genetics healthcare professionals feel unprepared to handle these requests," Tracey Weiler, an associate professor at Florida International University, added during the session, noting that no recommendations exist to steer how PCPs handle DTC genetic testing results. "And furthermore, many genetics professionals have questions and concerns about DTC-GT growth and the manner in which DTC results are being interpreted and utilized in clinical medicine."
Because of that, the Inter-Society Coordinating Committee for Practitioner Education in Genomics/National Institutes of Health DTC-GT Project Group is developing guidelines for PCPs about how to manage DTC genetic testing results they may encounter. The group further asked during the session for ACMG members to weigh in on draft guidelines that are to form the basis of a white paper.
While interpreting some DTC genetic testing results may be straightforward, other cases can be more complex, Massart added, and presented two such situations. In the first, a patient brought in a DTC genetic testing report suggesting she had a prothrombin mutation. The patient further had a personal and family history of thrombosis, and the DTC genetic testing was validated clinically and the patient was advised of risks and given guidelines for management.
The second case, though, was more complex, as the patient underwent DTC ancestry testing and uploaded the data to a third-party site, which suggested the patient had three pathogenic variants and was at risk of being a carrier for two different conditions. Personal and family history did have some overlap, but a clinical custom panel did not validate the three pathogenic variants.
Further, not all DTC genetic tests are the same, the speakers said, noting that their quality and the genes they cover may vary.
Due to that range in quality and coverage, Christine Formea, a health system pharmacogenomics clinical pharmacist at Intermountain Healthcare, said clinical confirmatory testing for nearly all DTC genetic testing results — particularly with respect to pharmacogenomic changes — should be performed. One exception she, said, would be a CYP2C19 test from 23andMe, which received 510(k) clearance from the US Food and Drug Administration in August 2020.
"Confirmatory testing should be conducted by a CLIA-certified laboratory before any medication changes are made by providers," Formea said, adding that patients, too, should not initiate such changes on their own without clinical confirmation.
The need for clinical validation is included in the draft guidelines the panel presented at the session for feedback via an online survey of the audience. The draft guidelines encourage PCPs to ask patients why they are interested in seeking or have sought DTC genetic testing and to determine whether the testing would be or was conducted in a CLIA-certified lab. If not conducted in a CLIA-certified lab, PCPs were advised to seek confirmatory clinical testing. Only confirmed results, they said, should be entered into patients' electronic health records. Otherwise, the results should be included in a clinical note.
The draft guidelines further outlined different scenarios that PCPs might encounter, such as patients who received a positive or a negative result from a CLIA-certified lab for a Mendelian condition, pharmacogenomic interaction, carrier status, or complex condition.
For example, for a positive result for a Mendelian condition from a CLIA-certified lab, the draft guidelines recommend that PCPs evaluate the patient for symptoms of the condition, determine if there is a family history, and refer the patient to a genetics professional. Following counseling, they then recommend confirmatory testing, if available, if increased screening or other intervention is warranted, as well as referral to preconception genetic counseling if the variant could be passed on to offspring.
In the question-and-answer part of the session, the panel received some pushback on the recommendation that DTC genetic testing results should not be included in patients' electronic health records. In particular, the critics noted that DTC test results should be documented, particularly if they are to be later acted upon. Additionally, if they are recorded only in clinical notes, they could get lost or overlooked by providers.
The panel's Mathew Taylor, the director of adult clinical genetics at the University of Colorado Anschutz Medical Center, said they would take the feedback under advisement and that the point that "if things aren't in the medical record, then it's difficult to adjudicate them as we go forward" was well taken.
The panel noted that the survey was being left open for the time being for wider feedback.