Comparison of 12 Molecular Detection Assays for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2)

Molecular testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the mainstay for accurate diagnosis of the infection, but the diagnostic performances of available assays have not been defined. We compared 12 molecular diagnostic assays, including 8 commercial kits using 155 respiratory samples (65 nasopharyngeal swabs, 45 oropharyngeal swabs, and 45 sputum) collected at two Japanese hospitals. Sixty-eight samples were positive for more than one assay and one genetic locus, and were defined as true-positive samples. All the assays showed a specificity of 100% (95% CI, 95.8%-100%). The N2 assay kit of the US Centers for Disease Control and Prevention and the N2 assay of the Japanese National Institute of Infectious Disease (NIID) were the most sensitive assays with 100% sensitivity (95% CI, 94.7-100), followed by the Centers for Disease Control and Prevention N1 kit, E assay by Corman, and Japanese National Institute of Infectious Disease N2 assay multiplex with internal control reactions. These assays are reliable as first-line molecular assays in laboratories when combined with appropriate internal control reactions.