While real-time reverse transcription polymerase chain reaction (RT PCR) assays are the primary diagnostic for COVID-19, the U.S. Food and Drug Administration (FDA) has also granted Emergency Use Authorization (EUA) to dozens of antibody tests since the pandemic began. And that begs an important question: Which of these tests is most reliable? The FDA recently published comparison data purporting to answer that question. The Role of Antibody Testing Serology-based tests detect antibodies the body produces to fight SARS-CoV-2 rather than the virus itself. The problem is that it takes several days for people who are infected to develop antibodies to the virus. This limits their reliability in diagnosing COVID-19. But while they should not be used as the sole basis for diagnosis, antibody tests help healthcare professionals identify individuals who may have developed an immune response to SARS-CoV-2 and determine who can donate convalescent plasma to treat patients with infections. The FDA Performance Evaluation Methodology As with any other assay, some SARS-CoV-2 antibodies tests are more reliable than others. The FDA set out to evaluate performance of 64 EUA tests on the basis of data provided by the respective test manufacturers and using two key metrics: “Sensitivity” measures the ability […]