Clinical evaluation of commercial automated SARS-CoV-2 immunoassays

Kittel, M.; Muth, M.; Zahn, I.; Roth, P.; Thiaucourt, M.; Gerhards, C.; Haselmann, V.; Neumaier, M.; Findeisen, P.

OBJECTIVE: Numerous immunoassays for detecting antibodies directed against SARS-CoV-2 have rapidly been developed and released. Validations of these have been performed with a limited number of samples. The lack of standardization might lead to significantly different results. This study compares ten automated assays from six vendors in terms of sensitivity, specificity, and reproducibility. METHODS: This study compared ten fully automated IAs from the following vendors: Diasorin, Epitope Diagnostics, Euroimmun, Roche, YHLO, and Snibe. The retrospective part of the study included patients with a laboratory-confirmed COVID-19 infection and controls comprised patients with a suspected infection, in whom the disease was excluded. Furthermore, biobanked sera were taken as negative controls (n = 97). The retrospective part involved four classes: 1) laboratory-confirmed COVID-19 infection (n = 183); 1B) suspected COVID-19 infection (n = 167) without qRT-PCR result but positive serological results from at least two different assays, and suspected COVID-19 infection due to a positive serological result from the Roche assay (n = 295); 2) biobanked sera obtained from patients before the emergence of SARS-CoV-2 (n = 97) as negative controls. 2A) probably COVID-19-negative sera with negative serological results from at least two different assays (n = 152). RESULTS: Overall diagnostic sensitivities were: Euroimmun(IgA) 87%; Epitope Diagnostics(IgG) 83%; YHLO(IgG) 77%; Roche(IgM/IgG) 77%; Euroimmun(IgG) 75%; Diasorin(IgG) 53%; Epitope Diagnostics(IgM) 52%; Snibe(IgG) 47%; YHLO(IgM) 35%; Snibe(IgM) 26%. Diagnostic specificities were: YHLO(IgG) 100%; Roche, 100%; Snibe(IgM/IgG) 100%; Diasorin(IgG) 97%; Euroimmun(IgG), 94%; YHLO(IgM) 94%; Euroimmun(IgA) 83%. CONCLUSION: Assays from different vendors vary substantially in terms of their performance. Our findings might facilitate the selection of appropriate serological assays.