Performance Characteristics of BinaxNOW COVID-19 Antigen Card for Screening Asymptomatic Individuals in a University Setting

We compared the performance of the Abbott BinaxNOW COVID-19 antigen card to that of a standard reverse transcription-PCR (RT-PCR) assay (Thermo Fisher TaqPath COVID-19 Combo kit) for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in 2,645 asymptomatic students presenting for screening at the University of Utah. SARS-CoV-2 RNA was detected in 1.7% of the study participants by RT-PCR. BinaxNOW identified 24 infections but missed 21 infections that were detected by RT-PCR. The analytical sensitivity (positive agreement) and analytical specificity (negative agreement) for the BinaxNOW were 53.3% and 100%, respectively, compared to the RT-PCR assay. The median cycle threshold (C(T)) value in the specimens that had concordant positive BinaxNOW antigen results was significantly lower than that of specimens that were discordant (C(T) of 17.6 versus 29.6; P < 0.001). In individuals with presumably high viral loads (C(T) of <23.0), a 95.8% positive agreement was observed between the RT-PCR assay and BinaxNOW. Due to the possibility of false-negative results, caution must be taken when utilizing rapid antigen testing for screening asymptomatic individuals.