Comparison of six commercially available SARS-CoV-2 antibody assays-Choice of assay depends on intended use

Objectives: Evaluate six commercial serological assays for detection of IgA, IgM or IgG SARS-CoV-2 antibodies in different disease severities. Methods: Three lateral flow tests (LFTs) (Acro IgM/IgG, CTK IgM/IgG, Livzon IgM/IgG) and three ELISA assays (Euroimmun IgA and IgG, Wantai IgM) were included. Application was evaluated using samples from 57 patients with a positive SARS-CoV-2 reverse transcription polymerase chain reaction, stratified according to disease severity. Specificity was assessed using historical samples from 200 blood donors. Results: While IgM LFTs failed to detect SARS-CoV-2 antibodies in 37-84% of non-hospitalised patients, the Wantai IgM ELISA detected antibodies in 79%. The Euroimmun IgG ELISA detected antibodies in 95% of non-hospitalised patients. IgA, IgM and IgG ELISA levels were initially low, increased over time, and correlated with disease severity. LFT sensitivity declined in samples taken >28 days after symptom onset/resolution. The Livzon IgG LFT had the highest specificity (98.5%), followed by the Euroimmun IgG ELISA (96.2%). The specificity for Euroimmun IgA ELISA improved (>= 97.5%) using a custom cut-off value (4.0). Conclusions: The sensitive and semi-quantitative ELISA assays are most appropriate for serologic detection of SARS-CoV-2 infection in mild cases. Livzon LFT and Euroimmun ELISA had the highest specificity among the IgG assays, making them most suitable for seroprevalence studies. (C) 2020 The Authors. Published by Elsevier Ltd on behalf of International Society for Infectious Diseases.

Automated summary

This study evaluated six commercial serological assays for detection of SARS-CoV-2 antibodies, finding that ELISA assays are most suitable for mild cases, while Livzon LFT and Euroimmun ELISA have the highest specificity, making them suitable for seroprevalence studies.