Sensitivity of SARS-CoV-2 antibody tests with late convalescent sera

Judith Kannenberg; Carolin Schnurra; Nina Reiners; Reinhard Henschler; Raymund Buhmann; Thorsten Kaiser; Ronald Biemann; Mario Hönemann; Grit Ackermann; Henning Trawinski; Christian Jassoy

doi:10.1016/j.jcvp.2021.100038

Sensitivity of SARS-CoV-2 antibody tests with late convalescent sera

J Clin Virol Plus. 2021 Sep;1(3):100038. doi: 10.1016/j.jcvp.2021.100038. Epub 2021 Aug 18.

Affiliations

¹ Institute for Medical Microbiology and Virology, University Hospital and Medical Faculty, University of Leipzig Germany.
² Institute of Transfusion Medicine, University Hospital and Medical Faculty, University of Leipzig Germany.
³ Institute for Laboratory Medicine, Clinical Chemistry and Molecular Diagnostics, University Hospital and Medical Faculty, University of Leipzig Germany.
⁴ Labor AlphaOmega, Leipzig, Germany.
⁵ Division of Infectious Diseases and Tropical Medicine, Department of Medicine II, Interdisciplinary Center for Infectious Diseases, Leipzig University Hospital, Leipzig, Germany.

Abstract

SARS-CoV-2-specific IgM antibodies wane during the first three months after infection and IgG antibody levels decline. This may limit the ability of antibody tests to identify previous SARS-CoV-2 infection at later time points. To examine if the diagnostic sensitivity of antibody tests falls off, we compared the sensitivity of two nucleoprotein-based antibody tests, the Roche Elecsis II Anti-SARS-CoV-2 and the Abbott SARS-CoV-2 IgG assay and three glycoprotein-based tests, the Abbott SARS-CoV-2 IgG II Quant, Siemens Atellica IM COV2T and Euroimmun SARS-CoV-2 assay with 53 sera obtained 6 months after SARS-CoV-2 infection. The sensitivity of the Roche, Abbott SARS-CoV-2 IgG II Quant and Siemens antibody assays was 94.3% (95% confidence interval (CI) 84.3-98.8%), 98.1 % (95% CI: 89.9-100%) and 100 % (95% CI: 93.3-100%). The sensitivity of the N-based Abbott SARS-CoV-2 IgG and the glycoprotein-based Euroimmun ELISA was 45.3 % (95% CI: 31.6-59.6%) and 83.3% (95% CI: 70.2-91.9%). The nucleoprotein-based Roche and the glycoprotein-based Abbott receptor binding domain (RBD) and Siemens tests were more sensitive than the N-based Abbott and the Euroimmun antibody tests (p = 0.0001 to p = 0.039). The N-based Abbott antibody test was less sensitive 6 months than 4-10 weeks after SARS-CoV-2 infection (p = 0.0001). The findings show that most SARS-CoV-2 antibody assays correctly identified previous infection 6 months after infection. The sensitivity of pan-Ig antibody tests was not reduced at 6 months when IgM antibodies have usually disappeared. However, one of the nucleoprotein-based antibody tests significantly lost diagnostic sensitivity over time.

Keywords: Antibody test; CMIA, chemiluminescence microparticle immuno-assay; COVID-19; COVID-19, Corona-virus disease 2019; ECLIA, electrochemiluminescence immunoassay; ELISA, enzyme immunoassay; Late convalescent sera; MIA, microparticle immunoassay; N, nucleoprotein; RBD, receptor binding domain; SARS-CoV-2, Severe acute respiratory syndrome coronavirus-2; Sensitivity; Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2).