Reliable quantification of the antibody response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is highly relevant, e.g., for identifying possible vaccine failure and estimating the time of protection. Nonetheless, rapid antigen testing quickly identifies positive among those with symptoms and/or close contact exposure and could expedite isolation and treatment.
BinaxNOW has high accuracy among symptomatic individuals and is below the FDA threshold for emergency use authorization in asymptomatic individuals.
Specificity was greater than 99% for all groups. Sensitivity was 82% (95% CI 66%, 91%) for asymptomatic individuals with potential exposure and 64% (95% CI 51%, 76%) for those with no exposure. It was higher in symptomatic (87% 95% CI 80%, 91%) than asymptomatic (71% 95% CI 61%, 80%) individuals. Overall test sensitivity compared with reference laboratory reverse-transcription PCR testing was 81% (95% confidence interval 75%, 86%). Most (89%) were asymptomatic, of whom 17% reported potential exposure. Participants were grouped by self-reported COVID-19 exposure and symptom status. We describe our implementation and assess performance of the BinaxNOW COVID-19 Antigen Test (Abbott Laboratories) in 6,099 adults at a self-referred walk-up testing site. Rapid antigen tests are simple to perform and provide results within 15 min.
