Clinical Assessment of the Roche SARS-CoV-2 Rapid Antigen Test

Background. Novel point-of-care antigen assays present a promising opportunity for rapid screening for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. The purpose of this study was the clinical assessment of the new Roche SARS-CoV-2 Rapid Antigen Test.Methods. The clinical performance of Roche SARS-CoV-2 Rapid Antigen Test was evaluated versus a reverse transcription polymerase chain reaction (RT-PCR) laboratory-based assay (Seegene AllplexTM2019-nCoV) in nasopharyngeal swabs collected from a series of consecutive patients referred for SARS-CoV-2 diagnostics to Pederzoli Hospital (Peschiera del Garda, Verona, Italy) over a 2-week period.Results. The final study population consisted of 321 consecutive patients (mean age, 46 years and IQR, 32-56 years; 181 women, 56.4%), with 149/321 (46.4%) positive for SARS-CoV-2 RNA via the Seegene AllplexTM2019-nCoV Assay, and 109/321 (34.0%) positive with Roche SARS-CoV-2 Rapid Antigen Test, respectively. The overall accuracy of Roche SARS-CoV-2 Rapid Antigen Test compared to molecular testing was 86.9%, with 72.5% sensitivity and 99.4% specificity. Progressive decline in performance was observed as cycle threshold (Ct) values of different SARS-CoV-2 gene targets increased. The sensitivity was found to range between 97-100% in clinical samples with Ct values <25, between 50-81% in those with Ct values between 25-<30, but low as 12-18% in samples with Ct values between 30-<37.Conclusions. The clinical performance of Roche SARS-CoV-2 Rapid Antigen Test are excellent in nasopharyngeal swabs with Ct values <25, which makes it a reliable screening test in patients with high viral load. However, mass community screening would require the use of more sensitive techniques.