Comparison of three automatic chemiluminescent immunoassays for monitoring dynamic profile of SARS-CoV-2 IgG and IgM

Abstract

Background: Seldom performance evaluation and diagnosis comparison studies were reported for different chemiluminescent immunoassay (CLIA) kits approved under an emergency approval program for SARS-CoV-2 infection. Methods: A total of 100 and 105 serum separately from non-infected populations and COVID-19 patients were detected with SARS-CoV-2 IgM and IgG kits. The characteristics including precision, functional sensitivity, linearity, and accuracy were evaluated for Axceed, iFlash, and Maglumi CLIA kits. Results: Maglumi and iFlash had the best analytical sensitivity for IgM and IgG, respectively. Axceed kits had a linearity response in the detected concentration. The clinical sensitivity of Axceed, iFlash, and Maglumi was 68.0%, 64.9%, and 63.9% with a specificity of 99.0%, 96.0%, and 100% for IgM, 85.6%, 97.9%, and 94.8% with a specificity of 97.0% for IgG. ROC analysis indicated all kits had a diagnostic power greater than 0.9. Notably, either IgM or IgG kits obtained a poor agreement (Kappa value from 0.397 to 0.713) with others. Among 38 recovered patients, 94.7% had an effective immune response, and both seropositive IgM and IgG accounted for the biggest proportion (medium, 42 days onset), then followed by the single seropositive IgG (medium, 50 days onset) in Ab profile. Conclusion: The performance of CLIA kits satisfied the diagnosis of SARS-CoV-2 infection. Both positive of IgG and IgM contributes to improve the specificity, and a positive one will enhance the sensitivity.