Universal admission screening for COVID-19 using quantitative antigen testing and questionnaire screening to prevent nosocomial spread

BACKGROUND: In this study, we investigated diagnostic accuracy of quantitative severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigen testing and whether universal screening was effective to prevent a nosocomial outbreak of coronavirus disease 2019 (COVID-19). METHODS: All adult patients admitted to an acute-care hospital in Tokyo, Japan, after receiving LUMIPULSE SARS-CoV-2 Ag using a nasopharyngeal swab and a brief questionnaire to evaluate symptoms and exposures from December 3, 2020 to March 20, 2021 were included. RESULTS: Of the 5191 patients, 53 were antigen-positive, 19 were inconclusive and 5119 were negative. The sensitivity and specificity (positive or inconclusive results) of the quantitative antigen test for COVID-19 diagnosis at admission was 0.957 (95% confidence interval [CI]: 0.855–0.995) and 0.995 (95% CI: 0.992–0.997), respectively. Six asymptomatic patients were identified on admission. Two patients were antigen-negative and diagnosed with COVID-19 later; however, they had been isolated prior to diagnosis because both had symptoms of COVID-19 and exposure. No nosocomial infections occurred during the period. CONCLUSION: Quantitative SARS-CoV-2 antigen testing was found to be valid for the early detection of asymptomatic COVID-19 patients as a universal screening test on admission.