How Sensitive and Specific are Rapid Antigen Tests for SARS-CoV-2 – The Experience of One of the Biggest Bulgarian Hospitals

Abstract

Rapid point-of-care tests that detect antigens specific for SARS-CoV-2 are less expensive and faster than the standard molecular methods. However, their accuracy varies widely between tests, populations and settings. We decided to assess the diagnostic precision of antigen tests for SARS-CoV-2 in a real-life hospital environment. In a cohort of 2677 hospitalized patients, we found a sensitivity of 60.2% (95% CI 57.1%-63.4%) and a specificity of 98.1% (95% CI 97.4%-98.7%) for the antigen tests when compared to RT-PCR. The accuracy of antigen testing could be acceptable in a hospital setting, especially when the result is consistent with the clinical and epidemiological context. When there is discordance between the antigen test result and the patient’s symptoms, a confirmation with molecular methods is needed.

Keywords

• covid-19
• sensitivity
• specificity
• point-of-care systems