Clinical performances of three fully automated anti-SARS-CoV-2 immunoassays targeting the nucleocapsid or spike proteins

INTRODUCTION: This study assesses the clinical performances of three anti-SARS-CoV-2 assays, namely EUROIMMUN anti-SARS-CoV-2 nucleocapsid (IgG) ELISA, Elecsys anti-SARS-CoV-2 nucleocapsid (total antibodies) assay, and LIAISON anti-SARS-CoV-2 spike proteins S1 and S2 (IgG) assay.

METHODS: One hundred and thirty-seven COVID-19 samples from 96 RT-PCR confirmed patients were used to perform the sensitivity analysis. Non-SARS-CoV-2 sera (n = 141) with a potential cross-reaction to SARS-CoV-2 immunoassays were included in the specificity analysis.

RESULTS: None of these tests demonstrated a sufficiently high clinical sensitivity to diagnose acute infection. Fourteen days since symptom onset, we did not reveal any significant difference between the three techniques in terms of sensitivities. However, the Elecsys performed better in terms of specificity.

CONCLUSION: All three anti-SARS-CoV-2 assays had equivalent sensitivities 14 days from symptom onset to diagnose past-COVID-19 infection. We also confirmed that anti-SARS-CoV-2 determination before day 14 is of less clinical interest. This article is protected by copyright. All rights reserved.