Antibody response against SARS-CoV-2 spike protein and nucleoprotein evaluated by four automated immunoassays and three ELISAs. (November 2020)

• Record Type: Journal Article
• Authors: Van Elslande, Jan; Decru, Bram; Jonckheere, Stijn; Van Wijngaerden, Eric; Houben, Els; Vandecandelaere, Patricia; Indevuyst, Christophe; Depypere, Melissa; Desmet, Stefanie; André, Emmanuel; Van Ranst, Marc; Lagrou, Katrien; Vermeersch, Pieter
• Is Part Of: Clinical microbiology and infection. Volume 26:Number 11(2020)
• Page Start: 1557.e1
• Page End: 1557.e7
• Publication Date: 2020-11
• Subjects: Coronavirus -- COVID-19 -- Diagnosis -- ELISA -- Immunoassay -- Nucleocapsid protein -- SARS-CoV-2 -- Sensitivity and specificity -- Seroconversion -- Spike glycoprotein; Medical microbiology -- Periodicals; Diagnostic microbiology -- Periodicals; Communicable diseases -- Periodicals; Infection -- Periodicals; 616.01
• DOI: 10.1016/j.cmi.2020.07.038
• Languages: English
• ISSNs: 1198-743X

Abstract

Abstract: Objectives: The aim was to determine the antibody response against SARS-CoV-2 spike protein and nucleoprotein using four automated immunoassays and three ELISAs for the detection of total Ig antibodies (Roche) or IgG (Abbott, Diasorin, Snibe, Euroimmun, Mikrogen) in COVID-19 patients. Methods: Sensitivity and dynamic trend to seropositivity were evaluated in 233 samples from 114 patients with moderate, severe or critical COVID-19 confirmed with PCR on nasopharyngeal swab. Specificity was evaluated in 113 samples collected before January 2020, including 24 samples from patients with non-SARS coronavirus infection. Results: Sensitivity for all assays was 100% (95% confidence interval 83.7–100) 3 weeks after onset of symptoms. Specificity varied between 94.7% (88.7–97.8) and 100% (96.1–100). Calculated at the cut-offs that corresponded to a specificity of 95% and 97.5%, Roche had the highest sensitivity (85.0% (79.8–89.0) and 81.1% (76.6–85.7), p < 0.05 except vs. Abbott). Seroconversion occurred on average 2 days earlier for Roche total Ig anti-N and the three IgG anti-N assays (Abbott, Mikrogen, Euroimmun) than for the two IgG anti-S assays (Diasorin, Euroimmun) (≥50% seroconversion day 9–10 vs. day 11–12 and p < 0.05 for percent seropositive patients day 9–10 to 17–18). There was no significant difference in the IgG antibody time to seroconversion between critical and non-critical patients. Discussion: Seroconversion occurred within 3 weeks after onset of symptoms with all assays and on average 2 days earlier for assays detecting IgG or total Ig anti-N than for IgG anti-S. The specificity of assays detecting anti-N was comparable to anti-S and excellent in a challenging control population.