The gold standard for diagnostic testing for SARS-CoV-2 is real-time reverse transcriptase–polymerase chain reaction (RT-qPCR). Because of lag times in obtaining results and the expense of this diagnostic modality, rapid antigen testing has been frequently used for screening of asymptomatic populations instead. Several SARS-CoV-2 rapid antigen tests are available in the U.S. with Emergency Use Authorization by the Food and Drug Administration based on data from symptomatic patients. Although rapid antigen tests have been criticized for poor sensitivity and specificity when screening asymptomatic patients, a knowledge gap still remains regarding the utility of these tests for screening. Given the large cohort of individuals being screened by an international service company based in New York City, Connor, et al. (2022) sought to analyze the comparative effectiveness and estimated accuracy of an employee screening program using single vs repeated antigen tests compared with RT-qPCR among asymptomatic individuals.
A total of 179,127 participants underwent testing and were included in the analysis. The median age was 36 years (range, 18-65 years); 58% were male, 36% were female, and gender was unknown for 6%. A total of 179,127 rapid SARS-CoV-2 antigen tests were performed, with a 0.35% positivity rate (623 positive antigen test results) between November 2020 and October 2021. Of 623 total positive test results, 238 (38%) were confirmed to be true positive and 385 (62%) false positive by RT-qPCR. Of the 623 tests with positive results, 569 (91%) were followed by a second rapid antigen test. Of 224 sets of tests with concordant results (2 separate but consecutive antigen tests with positive results), RT-qPCR results were positive for 207 (92%). When the result of the first antigen test was positive and the result of the second antigen test was negative (n = 345), RT-qPCR results were negative for 328 (95%).
Reference: Connor BA, et al. Comparative Effectiveness of Single vs Repeated Rapid SARS-CoV-2 Antigen Testing Among Asymptomatic Individuals in a Workplace Setting. JAMA Netw Open. 2022;5(3):e223073. doi:10.1001/jamanetworkopen.2022.3073