Comprehensive evaluation of eight commercial SARS-CoV-2 IgG assays

Abstract

Sensitivity and specificity of serological assays are key parameters for the accurate estimation of SARS-CoV-2 sero-prevalence. The aim of this study was to compare 8 readily available IgG antibody tests using a panel of well-defined serum samples of prepandemic and pandemic origin. A cross-reaction panel included samples of patients with recent infection with either of the endemic Coronaviruses 229E, NL63, HKU1, or OC43. Additionally, samples with high antibody levels against influenza virus, adenovirus, and during acute EBV infection were included. Previous infection with endemic coronaviruses caused a significant amount of cross-reactivity in two of the assays. In contrast, the confidence intervals for the assays of Abbott, DiaSorin, Euroimmun and Roche encompassed the value of 98% for samples with a previous endemic HCoV infection. For all assays, sensitivities were between 91.3% and 98.8%. Assay performance was independent of the usage of either nucleocapsid or spike proteins.

Keywords: Covid-19; Cross-reactivity; SARS-CoV-2; Sensitivity; serology.

Fig. 1

Correlation of quantitative assay results of serum samples of patients with a known SARS-CoV-2 infection. Each scatter plot represents the test results of two assays to show interassay correlation (left part). Each dot represents one sample (pandemic samples of SARS-CoV-2 NAAT positive patients). Spearman-Rho correlation coefficient (ρ) is shown on the right part. All correlations are significant (P≤ 0.01), except for ⁺(significant; 0.01> P≤ 0.05) and ^‡(not significant). Variable distribution for each assay and test specific units are displayed on the diagonal. (Epitope D, Epitope Diagnostics; Euro, Euroimmun.)