Sensitivity of the Elecsys Anti-SARS-CoV-2 immunoassay as an aid in determining previous exposure to SARS-CoV-2

Hegel, J. K.; Riester, E.; Rank, C. M.; Langen, F.; Laengin, T.; Findeisen, P.

Background: The Elecsys(R) Anti-SARS-CoV-2 electrochemiluminescence immunoassay (Roche Diagnostics International Ltd) was developed for the in vitro qualitative detection of antibodies to SARS-CoV-2. We evaluated the sensitivity of the Elecsys Anti-SARS-CoV-2 immunoassay in samples from a diverse cross-section of patients across multiple sites and compared results against commercially available comparators. Methods: Sensitivity of the Elecsys Anti-SARS-CoV-2 immunoassay was evaluated using anonymised, frozen, residual single and sequential serum and plasma samples from patients with polymerase chain reaction (PCR)-confirmed SARS-CoV-2 infection. Point estimates and 95% confidence intervals (CIs) were calculated and method comparisons performed versus the following comparator assays: Euroimmun Anti-SARS-CoV-2 IgG, Abbott ARCHITECT SARS-CoV-2 IgG, Siemens ADVIA Centaur SARS-CoV-2 Total, and YHLO iFlash SARS-CoV-2 IgG and IgM. Results: Overall sensitivity for the Elecsys Anti-SARS-CoV-2 immunoassay in 219 samples drawn [≥]14 days post-PCR confirmation was 93.6% (95% CI 89.5-96.5). Across the three study sites, sensitivity in samples drawn [≥]14 days post-PCR confirmation ranged from 85.7-98.9%. Sensitivity was significantly higher for the Elecsys Anti-SARS-CoV-2 immunoassay compared with the YHLO iFlash SARS-CoV-2 IgM assay for samples drawn [≥]14 days post-PCR confirmation (86.3% [95% CI 76.7-92.9] versus 33.8% [95% CI 23.6-45.2]). Both Siemens ADVIA Centaur SARS-CoV-2 Total and YHLO iFlash SARS-CoV-2 IgG assays had a significantly higher sensitivity compared with the Elecsys Anti-SARS-CoV-2 immunoassay for samples drawn [≥]14 days post-PCR confirmation (95.1% [95% CI 87.8-98.6] versus 85.2% [95% CI 75.6-92.1]; 93.8% [95% CI 86.0-97.9] versus 86.3% [95% CI 76.7-92.9]). Differences in sensitivity between the Elecsys Anti-SARS-CoV-2 immunoassay and the Euroimmun Anti-SARS-CoV-2 IgG (90.3% [95% CI 83.7-94.9] versus 95.2% [95% CI 89.8-98.2]) and Abbott ARCHITECT SARS-CoV-2 IgG (84.8% [95% CI 75.0-91.9] versus 87.3% [95% CI 78.0-93.8]) assays for samples drawn [≥]14 days post-PCR confirmation were not significant. Conclusions: The Elecsys Anti-SARS-CoV-2 immunoassay demonstrated high sensitivity in samples collected [≥]14 days post-PCR confirmation of SARS-CoV-2 infection, and comparable sensitivity to several commercially available comparator assays across multiple sites, supporting the use of this assay as a tool to aid in determination of previous exposure to SARS-CoV-2.