Abstract
Aims: The aim of this study was to evaluate the performance of the automated Elecsys® SARS-CoV-2 antigen assay compared to RT-PCR taken as the gold standard for SARS-CoV-2 detection.
Methods: 225 nasopharyngeal swabs were randomly collected among which 123 were tested positive and 102 negatives for SARS-CoV-2 based on RT-PCR. Antigen dosing were performed on a Cobas 8000 e801 analyzer.
Results: The antigen test diagnosed SARS-CoV-2 infection status with an overall sensitivity of 65,85% (95% CI 56,76-74,16%), a specificity of 100% (95% CI 96,49-100%) with a Cut-off value ≥ 1. When the cut-off value for the antigen assay was set to > 0,673 COI, the accuracy reached its highest level with a sensitivity of 74,8% (95% CI 66,2 – 82,2%) and a specificity of 97,1% (95% CI 91,6 – 99,4%). Imprecision was estimated in accordance with manufacturer’s claims.
Conclusions: We obtained an overall sensitivity of 65,85% (95% CI 56,76-74,16%) and a specificity of 100% (95% CI 96,49-100%), slightly higher than the results reported by the manufacturer. Yet, it remains relatively low comparatively to what is generally acceptable for these antigenic assays (a relative sensitivity of 80%). We also noticed that the accuracy could reach its highest level if the cut-off is set above 0,673 which is lower than established by the manufacturer. Thus, our results suggest that the Elecsys® SARS-CoV-2 Antigen assays, should be improved prior to be used in a SARS-Cov-2 screening strategy. However, if one antigenic assay could demonstrate acceptable performance, it might be centralized in clinical laboratories, keeping the RT-PCR in a second phase for confirmation.
Keywords: Automated antigen immunoassay; COVID-19; SARS-CoV-2 testing strategy; Sensitivity.
【저자키워드】 COVID-19, sensitivity, SARS-CoV-2 testing strategy, Automated antigen immunoassay, 【초록키워드】 SARS-CoV-2, SARS-COV-2 infection, RT-PCR, Antigen, Nasopharyngeal swab, SARS-CoV-2 detection, sensitivity, specificity, Accuracy, SARS-CoV-2 testing, nasopharyngeal swabs, gold, automated, SARS-CoV-2 antigen, 95% CI, confirmation, gold standard, antigenic, cut-off value, cut-off, positive, screening strategy, Elecsys, Randomly, relative sensitivity, highest, tested, performed, collected, evaluate, reported, assays, diagnosed, reached, 【제목키워드】 SARS-CoV-2, Nasopharyngeal swab, Elecsy,