Evaluation of nine commercial SARS-CoV-2 immunoassays

Ria Lassaunière; Anders Frische; Zitta B Harboe; Alex CY Nielsen; Anders Fomsgaard; Karen A Krogfelt; Charlotte S Jørgensen

The clinical sensitivity of IgM for early diagnosis of COVID-19 is currently unclear. SARS-CoV-2-specific IgM does not consistently appear before its IgG counterpart, with some studies reporting detection of SARS-CoV-. CC-BY 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. In conclusion, our findings show that in an ELISA format the sensitivity of detecting total SARS-CoV-2 RBDspecific antibodies is higher than that of assays detecting spike-specific IgA or IgG only. It is important to note that the presence of SARS-CoV-2-specific antibodies does not necessarily correspond to protection against SARS-CoV-2 infection and disease. In order to define antibody-mediated protection, further investigation of virus-specific antibody functions that include neutralization and Fc-mediated effector functionality are needed. Sero-epidemiological investigations together with longitudinal studies on sequential samples taken from SARS-CoV-2 patients are necessary to characterize the spread of the virus and the long term protection of the antibodies measured. Due to comparatively poorer assay performance in an initial round of testing, further testing were suspended.