NEW YORK – The US Food and Drug Administration on Tuesday published information for labs and health care providers detailing the impact of SARS-CoV-2 mutations on molecular, antigen, and serology tests for the virus.
While the agency said that changes in the virus's genome may impact the effectiveness of antigen and serology tests, it noted in particular four molecular tests that received Emergency Use Authorization whose performance it said could be negatively affected by SARS-CoV-2 mutations: Mesa Biotech's Accula SARS-CoV-2 Test; Applied DNA Sciences' Linea COVID-19 Assay Kit; Thermo Fisher Scientific's TaqPath COVID-19 Combo Kit; and Cepheid's Xpert Xpress SARS-CoV-2, Xpert Xpress SARS-CoV-2 DoD, and Xpert Omni SARS-CoV-2 tests.
The agency noted in the case of the Accula test that the impact of the variant of concern "does not appear to be significant," but that it has alerted healthcare providers "out of an abundance of caution."
In the case of the Applied DNA Sciences, Thermo Fisher, and Cepheid tests, FDA said that certain mutations can reduce sensitivity for targets of each of these tests, but it added that because these tests all detect multiple genetic targets, it should not decrease overall test sensitivity. However, the impact of SARS-CoV-2 variants on these tests may affect the interpretation of results.
Additionally, FDA noted that for the Thermo Fisher and Applied DNA Sciences tests, cases in which the tests' fail to detect their S-gene targets but successfully detect their other targets may indicate the presence of certain mutations including those in the B117 variant, and labs should consider having such specimens sequenced if that service is available.
FDA said it will continue to update the page as new information on the impact of variants on SARS-CoV-2 testing becomes available.