ABSTRACT
Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) has sev-eral structural proteins including the spike (S) protein, which is the main target of current vaccines. There are various methodologies for the mea-surement of antibodies against it that provide information about the im-mune response to vaccination. The objective of this study was to determine the correlation between chemiluminescence (CLIA) and enzyme-linked im-munoassay (ELISA) for the measurement of IgG anti-S protein (IgG anti-S) antibodies. Serological results were collected from 169 individuals and antibody levels were determined by both methodologies. Out of the total samples, 106 were positive by both methodologies and 15 were discordant (CLIA+, ELISA-), with a Kappa index of 0.80. The correlation between both methodologies was good. This study could contribute to the management and follow-up of the vaccinated population, in order to obtain a cut-off value to evaluate the appli-cation of an additional dose.