A Real-World Comparison of SARS-CoV-2 Rapid Antigen Testing versus PCR Testing in Florida
Lao‐Tzu Allan‐Blitz, Jeffrey D. Klausner
Abstract
The reported sensitivity of rapid, antigen-based diagnostics for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection varies. Few studies have evaluated rapid antigen tests in real-world settings or among large populations. Beginning October 2020, Florida offered individuals presenting for SARS-CoV-2 testing PCR testing if they tested positive by the Abbott BinaxNOW COVID-19 antigen (Ag) card, were symptomatic, or required or requested PCR testing. We compared results among individuals who received both types of tests at four publicly accessible testing sites across Florida. We calculated the positive percent agreement (PPA) between the two test types by symptom status. Subsequently, we evaluated the PPA among individuals regardless of symptoms with lower cycle threshold values (<30). Overall, 18,457 individuals were tested via both methods, of which 3,153 (17.1%) were positive by PCR. The PPA for the Abbott BinaxNOW COVID-19 Ag card using the PCR comparator was 49.2% (95% confidence interval [CI], 47.4% to 50.9%). Among symptomatic individuals the PPA was 51.9% (95% CI, 49.7% to 54.0%). When restricted to positive PCR tests with a cycle threshold value of <30, regardless of symptom status, the PPA was 75.3% (95% CI, 72.8% to 77.6%). The PPA of the Abbott BinaxNOW COVID-19 Ag card compared with PCR was lower than that previously reported. Our findings may reflect the performance of the BinaxNOW antigen test in real-world settings.