The Elecsys® Anti-SARS-CoV-2 immunoassay (Roche Diagnostics) was developed to provide accurate, reliable detection of antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We evaluated sensitivity, specificity, cross-reactivity, and agreement with a vesicular stomatitis virus-based pseudo-neutralisation assay for the Elecsys Anti-SARS-CoV-2 immunoassay.
Sensitivity and agreement between the Elecsys Anti-SARS-CoV-2 immunoassay and pseudo-neutralisation assay measurements were evaluated using samples from patients with polymerase chain reaction (PCR)-confirmed SARS-CoV-2 infection, a majority of whom were hospitalised. Specificity was evaluated using samples from routine diagnostic testing/blood donors collected pre-December 2019 and thus deemed negative for SARS-CoV-2-specific antibodies. Cross-reactivity was evaluated using samples containing a wide range of potentially cross-reacting analytes, purchased from commercial vendors. For sensitivity and specificity, point estimates and 95% confidence intervals (CIs) were calculated. Agreement between the Elecsys Anti-SARS-CoV-2 immunoassay and pseudo-neutralisation assay was calculated.
Sensitivity of the Elecsys Anti-SARS-CoV-2 immunoassay in patients with prior PCR-confirmed SARS-CoV-2 infection was 99.5% (95% CI 97.0–100.0) at ≥14 days post-PCR confirmation. Overall specificity (n=10,453) was 99.80% (99.69–99.88). Only 4/792 samples containing potential cross-reacting analytes were reactive with the Elecsys Anti-SARS-CoV-2 immunoassay, resulting in an overall specificity in this cohort of 99.5% (98.6–99.9). Positive, negative and overall agreement (n=46) between Elecsys Anti-SARS-CoV-2 immunoassay and a pseudo-neutralisation assay were 86.4% (73.3–93.6), 100% (34.2–100) and 87.0% (74.3–93.9), respectively.
The Elecsys Anti-SARS-CoV-2 immunoassay demonstrated high sensitivity (99.5% at ≥14 days post-PCR confirmation) and specificity (99.80%), supporting its use as a tool for identification of past SARS-CoV-2 infection, including in populations with low disease prevalence.