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-KR (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 RTPCR. 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 RTPCR 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.

Automated summary

The performance of Abbott BinaxNOW COVID-19 antigen card was compared to a standard RT-PCR assay for detecting SARS-CoV-2 in asymptomatic students. Results showed lower sensitivity but higher specificity for BinaxNOW compared to RT-PCR, indicating caution is needed when using rapid antigen testing for screening asymptomatic individuals.