Performance evaluation of the Roche Elecsys Anti-SARS-CoV-2 S immunoassay

Background The Elecsys ® Anti-SARS-CoV-2 S immunoassay (Roche Diagnostics International Ltd, Rotkreuz, Switzerland) has been developed for the in vitro quantitative detection of antibodies to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) protein. We evaluated the performance of this assay using samples from seven sites in Germany, Austria, and Switzerland. Methods Anonymized frozen, residual serum, or plasma samples from blood donation centers or routine diagnostic testing were used for this study. For specificity and sensitivity analyses, presumed negative samples collected before October 2019 and SARS-CoV-2 PCR-confirmed single or sequential samples were tested, respectively. The performance of the Elecsys Anti-SARS-CoV-2 S immunoassay was also compared with other commercial immunoassays. Results The overall specificity (n=7880 pre-pandemic samples) and sensitivity (n=240 PCR-positive samples [≥14 days post-PCR]) for the Elecsys Anti-SARS-CoV-2 S immunoassay were 99.95% (95% confidence interval [CI]: 99.87–99.99) and 97.92% (95% CI: 95.21– 99.32), respectively. Compared with seven other immunoassays, the Elecsys Anti-SARS-CoV-2 S assay had comparable or greater specificity and sensitivity. The Elecsys Anti-SARS-CoV-2 S immunoassay had significantly higher specificity compared with the LIAISON ® SARS-CoV-2 S1/S2 IgG, ADVIA Centaur ® SARS-CoV-2 Total, ARCHITECT SARS-CoV-2 IgG, iFlash-SARS-CoV-2 IgM, and EUROIMMUN Anti-SARS-CoV-2 IgG and IgA assays, and significantly higher sensitivity (≥14 days post-PCR) compared with the ARCHITECT SARS-CoV-2 IgG, iFlash-SARS-CoV-2 IgG and IgM, and EUROIMMUN Anti-SARS-CoV-2 IgG assays. Conclusion The Elecsys Anti-SARS-CoV-2 S assay demonstrated a robust and favorable performance across samples from multiple European sites, with a very high specificity and sensitivity for the detection of anti-S antibodies.