Diagnostic accuracy of a SARS-CoV-2 rapid antigen test in real-life clinical settings

Background: Laboratory tests are a mainstay in managing the COVID-19 pandemic, and high hopes are placed on rapid antigen tests. However, the accuracy of rapid antigen tests in real-life clinical settings is unclear because adequately designed diagnostic accuracy studies are essentially lacking. Objectives: The aim of this study was to assess the accuracy of a rapid antigen test in diagnosing SARSCoV-2 infection in a primary/secondary care testing facility. Methods: Consecutive individuals presenting at a COVID-19 testing facility affiliated to a Swiss University Hospital were recruited ( n = 1465%). Nasopharyngeal swabs were obtained, and the Roche/SD Biosensor rapid antigen test was conducted in parallel with two real-time PCR tests (reference standard). Results: Among the 1465 patients recruited, RT-PCR was positive in 141 individuals, corresponding to a prevalence of 9.6%. The Roche/SD Biosensor rapid antigen test was positive in 94 patients (6.4%), and negative in 1368 individuals (93.4%; insufficient sample material in 3 patients). The overall sensitivity of the rapid antigen test was 65.3% (95% confidence interval ICI] 56.8-73.1), the specificity was 99.9% (95% CI 99.5-100.0). In asymptomatic individuals, the sensitivity was 44.0% (95% CI 24.4-65.1). Conclusions: The accuracy of the SARS-CoV-2 Roche/SD Biosensor rapid antigen test in diagnosing SARSCoV-2 infections in a primary/secondary care testing facility was considerably lower compared with the manufacturer's data. Widespread application in such a setting might lead to a considerable number of individuals falsely classified as SARS-CoV-2 negative. (c) 2021 The Authors. Published by Elsevier Ltd on behalf of International Society for Infectious Diseases. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/ )

Automated summary

The study assessed the accuracy of rapid antigen testing for diagnosing SARS-CoV-2 infection in a primary/secondary care testing facility. The results showed that the sensitivity of rapid antigen tests was lower than expected, potentially leading to individuals being falsely classified as negative.