Washington, DC–The U.S. Food and Drug Administration is alerting clinical laboratory staff and health care providers that the FDA is monitoring the potential impact of viral mutations, including an emerging variant from the United Kingdom known as the B.1.1.7 variant, on authorized SARS-CoV-2 molecular tests, and that false negative results can occur with any molecular test for the detection of SARS-CoV-2 if a mutation occurs in the part of the virus’s genome assessed by that test.
The SARS-CoV-2 virus can mutate over time, like all viruses, resulting in genetic variation in the population of circulating viral strains, as seen with the B.1.1.7 variant. The FDA is taking additional actions to ensure authorized tests remain accurate by working with test developers and conducting ongoing data analysis to evaluate all currently authorized molecular tests. The FDA believes the risk that these mutations will impact overall testing accuracy is low.
The FDA has been monitoring SARS-CoV-2 viral mutations, and potential impact on testing, throughout the pandemic. The presence of SARS-CoV-2 genetic variants in a patient sample can potentially change the performance of a SARS-CoV-2 test. Tests that rely on the detection of multiple regions of the genome may be less impacted by genetic variation in the SARS-CoV-2 genome than tests that rely on detection of only a single region.
Three currently authorized molecular tests, MesaBiotech Accula, TaqPath COVID-19 Combo Kit, and Linea COVID-19 Assay Kit, may be impacted by genetic variants of SARS-CoV-2, but the impact does not appear to be significant. Importantly, the detection pattern that appears with the TaqPath and Linea diagnostic tests when certain genetic variants are present may help with early identification of new variants in patients to reduce further spread of infection. The recently identified B.1.1.7 variant has been associated with an increased risk of transmission, therefore early identification of this variant in patients may help reduce further spread of infection.
The FDA has reminded clinical laboratory staff and health care providers about the risk of false negative results with all laboratory tests, including molecular tests. Laboratories should expect some false results to occur even when very accurate SARS-CoV-2 tests are used. Today’s announcement also provides important information and recommendations for clinical laboratory staff and health care providers who use molecular tests for the detection of SARS-CoV-2.