The FDA is alerting clinical laboratory staff and health care providers that genetic variants of SARS-CoV-2 may lead to false negative results with molecular tests for SARS-CoV-2.
Most molecular tests for SARS-CoV-2 are designed to detect specific RNA sequences found in the viral genome. However, the SARS-CoV-2 virus mutates regularly, resulting in several genetically unique variants, each with different RNA sequences, that may be found in infected individuals as the pandemic progresses.
The presence of SARS-CoV-2 genetic variants in a patient sample can potentially change the performance of the SARS-CoV-2 test. Molecular tests designed to detect multiple SARS-CoV-2 genetic targets are less susceptible to the effects of genetic variation than tests designed to detect a single genetic target.
The FDA recommends clinical laboratory staff and health care providers who use molecular tests for the detection of SARS-CoV-2 to:
Be aware that genetic variants of SARS-CoV-2 arise regularly and false negative test results can occur.
Be aware that tests that use multiple genetic targets to determine a final result are less likely to be impacted by increased prevalence of genetic variants.
Consider negative results in combination with clinical observations, patient history, and epidemiological information.
Consider repeat testing with a different test (with different genetic targets) if COVID-19 is still suspected after receiving a negative test result.
Based on FDA’s analysis to date, FDA is providing recommendations for clinical laboratory staff and health care providers using three specific tests that have been issued an Emergency Use Authorization: Accula SARS-CoV-2 test, TagPath COVID-19 Combo Kit and Linea COVID-19 Assay Kit. These recommendations are available here.
Food and Drug Administration (FDA). Genetic Variants of SARS-CoV-2 May Lead to False Negative Results with Molecular Tests for Detection of SARS-CoV-2 – Letter to Clinical Laboratory Staff and Health Care Providers. January 8, 2021. Available at: click here. Accessed January 8, 2021.