Performance Characteristics of the Abbott BinaxNOW SARS-CoV-2 Antigen Test in Comparison to Real-Time Reverse Transcriptase PCR and Viral Culture in Community Testing Sites during November 2020
Olivia Almendares, Jessica L. Prince-Guerra, Leisha D. Nolen, Jayleen K. L. Gunn, Ariella P. Dale, Sean A. Buono, Molly Deutsch-Feldman, Suganthi Suppiah, LiJuan Hao, Yan Zeng, Valerie A. Stevens, Kristen Knipe, Justine Pompey, Christine Atherstone, David P. Bui, Tracy Powell, Azaibi Tamin, Jennifer L. Harcourt, Marla Petway, Caitlin Bohannon, Jennifer M. Folster, Adam MacNeil, Reynolds Salerno, Wendi Kuhnert-Tallman, Jacqueline E. Tate, Natalie Thornburg, Hannah L. Kirking, Khalilullah Sheiban, Julie Kudrna, Theresa Cullen, Kenneth K. Komatsu, Julie M. Villanueva, Dale A. Rose, John C. Neatherlin, Mark Anderson, Paul A. Rota, Margaret A. Honein, William A. Bower
Abstract
Point-of-care antigen tests are an important tool for SARS-CoV-2 detection. Antigen tests are less sensitive than real-time reverse transcriptase PCR (rRT-PCR). Data on the performance of the BinaxNOW antigen test compared to rRT-PCR and viral culture by symptom and known exposure status, timing during disease, or exposure period and demographic variables are limited. During 3 to 17 November 2020, we collected paired upper respiratory swab specimens to test for SARS-CoV-2 by rRT-PCR and Abbott BinaxNOW antigen test at two community testing sites in Pima County, Arizona. We administered a questionnaire to capture symptoms, known exposure status, and previous SARS-CoV-2 test results. Specimens positive by either test were analyzed by viral culture. Previously we showed overall BinaxNOW sensitivity was 52.5%. Here, we showed BinaxNOW sensitivity increased to 65.7% among currently symptomatic individuals reporting a known exposure. BinaxNOW sensitivity was lower among participants with a known exposure and previously symptomatic (32.4%) or never symptomatic (47.1%) within 14 days of testing. Sensitivity was 71.1% in participants within a week of symptom onset. In participants with a known exposure, sensitivity was highest 8 to 10 days postexposure (75%). The positive predictive value for recovery of virus in cell culture was 56.7% for BinaxNOW-positive and 35.4% for rRT-PCR-positive specimens. Result reporting time was 2.5 h for BinaxNOW and 26 h for rRT-PCR. Point-of-care antigen tests have a shorter turnaround time than laboratory-based nucleic acid amplification tests, which allows for more rapid identification of infected individuals. Antigen test sensitivity limitations are important to consider when developing a testing program.