The US Food and Drug Administration has alerted health care providers and labs that genetic variants of the novel coronavirus — including an emerging variant first detected in the United Kingdom called B.1.1.7 — could lead to false negative Covid-19 test results.
The FDA noted in a news release on Friday afternoon that false negative results can occur with any molecular test for the detection of the virus if a mutation has occurred in the part of the virus's genome that the test examines. According to the FDA, the risk that these mutations will impact overall testing accuracy is low. If Covid-19 is suspected after a negative test, the agency recommends repeat testing with a different test.
The agency notes three Covid-19 tests authorized in the United States may be impacted by genetic variants — MesaBiotech Accula, TaqPath Covid-19 Combo Kit and Linea Covid-19 Assay Kit — "but the impact does not appear to be significant.”
Since the TaqPath and Linea Covid-19 tests detect multiple genetic targets, the overall test sensitivity should not be impacted, the FDA noted. However, if certain patterns emerge in individual results from those tests, labs might consider further genetic sequencing of specimens. That “may help with early identification of new variants in patients to reduce further spread of infection,” the FDA said in its letter to labs and health care providers, noting that the B.1.1.7 variant has been associated with an increased risk of transmission
"The FDA will continue to monitor SARS-CoV-2 genetic viral variants to ensure authorized tests continue to provide accurate results for patients," FDA Commissioner Dr. Stephen Hahn said in the release. SARS-CoV-2 is the name of the novel coronavirus that causes Covid-19.
"While these efforts continue, we are working with authorized test developers and reviewing incoming data to ensure that health care providers and clinical staff can quickly and accurately diagnose patients infected with SARS-CoV-2, including those with emerging genetic variants," Hahn said.
"At this time, we believe the data suggests that the currently authorized COVID-19 vaccines may still be effective against this strain. The FDA will continue to keep health care providers and the public informed of any new information as it becomes available."