Evaluation of a high volume antigen test for detection of SARS-CoV-2

Increasing transmission of SARS-CoV-2 infection in successive waves may strain the capacity of laboratories performing molecular diagnostic testing. Alternative testing approaches may offer additional diagnostic capacity. A high throughput chemiluminescent antigen assay (Ortho VITROS SARS-CoV-2 antigen test) was evaluated using both an inactivated virus preparation and prospective clinical samples (nasopharyngeal swabs in virus transport medium). The limit of detection of the assay was approximately 0.5 TCID(50)/ml, equivalent to a Ct value of 33. The assay was linear over a wide range. When 528 clinical samples were tested with the antigen assay, the sensitivity was 84.2% and the specificity was 100% (positive predictive value 100% and negative predictive value 97.7%). High volume antigen tests might be used to supplement molecular diagnostic testing capacity.