Challenges and Methodological Aspects of Detecting Anti-RBD Antibodies by ELISA in SARS-CoV-2 Research

Abstract The detection of IgE antibodies specific to the receptor-binding domain (RBD) of SARS-CoV-2 has been associated with aspects of COVID-19 severity, including potential mast cell–mediated mechanisms. Recent studies analyzed IgE anti-RBD across different COVID-19 severity groups using ELISA. The coating-antigen concentration influences the detection capacity of the immunoassay; thus, low-abundance antibodies, such as IgE, may require higher antigen concentrations to achieve optimal experimental conditions. Here, we present the effect of different coating concentrations for anti-RBD IgE and IgG4 detection in samples of vaccinated individuals. Our results suggested that intermediate antigen concentrations provide a better balance between sensitivity and specificity, highlighting the importance of methodological standardization.