Rapid antigen test to identify COVID-19 infected patients with and without symptoms admitted to the Emergency Department

PURPOSE: Early detection of SARS-CoV-2 patients is essential to contain the pandemic and keep the hospital secure. The rapid antigen test seems to be a quick and easy diagnostic test to identify patients infected with SARS-CoV-2. To assess the possible role of the antigen test in the Emergency Department (ED) assessment of potential SARS-CoV-2 infection in both symptomatic and asymptomatic patients. METHODS: Between 1 July 2020 and 10 December 2020, all patients consecutively assessed in the ED for suspected COVID-19 symptoms or who required hospitalisation for a condition not associated with COVID-19 were subjected to a rapid antigen test and RT-PCR swab. The diagnostic accuracy of the antigen test was determined in comparison to the SARS-CoV-2 PCR test using contingency tables. The possible clinical benefit of the antigen test was globally evaluated through decision curve analysis (DCA). RESULTS: A total of 3899 patients were subjected to antigen tests and PCR swabs. The sensitivity, specificity and accuracy of the antigen test were 82.9%, 99.1% and 97.4% (Cohen's K = 0.854, 95% CI 0.826-0.882, p