Clinical evaluation of four commercial immunoassays for the detection of antibodies against established SARS-CoV-2 infection

A comparison of the clinical performance of the Elecsys Anti-SARS-CoV-2, Liaison SARS-CoV-2 S1/S2 IgG, Access SARS-CoV-2 IgG and Vitros Immunodiagnostic Products Anti-SARS-CoV-2 IgG immunoassays for the diagnosis of COVID-19 infection was performed. Patient sera were collected at least 6 weeks following onset of COVID-19 infection symptoms. Negative control specimens were stored specimens from those without COVID-19, collected in April–May 2019. Sensitivity and specificity with 95% confidence intervals (CI) were calculated. Linear regression was used to examine the relationship between the magnitude of serological response and clinical characteristics. There were 80 patients from whom 86 sera specimens were collected; six patients had duplicate specimens. There were 95 negative control specimens from 95 patients. The clinical sensitivity of the Elecsys assay was 98.84% (95% CI 93.69–99.97), specificity was 100% (95% CI 96.19–100.00); the Liaison assay clinical sensitivity was 96.51% (95% CI 90.14–99.27), specificity was 97.89% (95% CI 92.60–99.74); the Access assay clinical sensitivity was 84.88% (95% CI 75.54–91.70), specificity was 98.95% (95% CI 94.27–99.97); and the Vitros assay clinical sensitivity was 97.67% (95% CI 91.85–99.72), specificity was 100% (95% CI 96.15–100.00). A requirement for hospitalisation for COVID-19 infection was associated with a larger Vitros, Liaison and Access IgG response whilst fever was associated with a larger Elecsys response. All assays evaluated with the exception of the Access assay demonstrated similar performance. The Elecsys assay demonstrated the highest sensitivity and specificity.