Comparison of eight commercial, high-throughput, automated or ELISA assays detecting SARS-CoV-2 IgG or total antibody

Abstract

Background: Many commercial assays, of different designs, detecting SARS-CoV-2-specific antibodies exist but with little experience with them.

Objectives: The aim of this study was to compare the performance of assays detecting IgG or total antibodies to N or S antigens, validated for routine use in France, with samples from subjects with more or less severe SARS-CoV-2 infection.

Methods: Eight assays were used: Abbott Architect, DiaSorin Liaison®, bioMérieux Vidas®, Roche Elecsys Cobas®, Siemens Atellica®, BioRad Platelia ELISA, Epitope Diagnostics ELISA, and Wantai ELISA. The tested population included 86 samples from 40 hospitalized subjects and 28 outpatients at different time from symptom onset.

Results: The positivity rate varied depending on the assay but was greater for all assays in hospitalized than non-hospitalized patients. Despite a good correlation between the assays, discrepancies occurred, without a systematic origin, even for samples taken more than 20 days after symptom onset. These discrepancies were linked to low antibody levels in pauci-symptomatic patients.

Conclusion: Whichever assay is chosen, a false negative result may need to be ruled out with another test in a risk situation.

Keywords: COVID-19; IgG; Immunoassay; SARS-CoV-2; Serology; Total Ig.