In order to identify the quantization capability of two methods for SARS-CoV-2 IgG determination (Anti-SARS-CoV-2 QuantiVac ELISA IgG from Euroimmun and SARS-CoV-2 IgG anti-RBD from SNIBE), the linearity of the reportable range with respect to the calibration curve was evaluated . The claimed reportable ranges are 6-120 RU/mL for Euroimmun method (positivity threshold 11 RU/mL) and 0.18-100 AU/mL for SNIBE method (positivity threshold 1 AU/mL). 29 serum specimens with different degrees of positivity from both patients recovered from COVID-19 and vaccinated subjects were evaluated (nine for SNIBE method and 20 for Euroimmun method). The results showed that both the methods could satisfactorily quantify anti SARS-CoV-2 antibodies, provided that the highest detectable value is fixed to 50 AU/mL for SNIBE and 100 RU/mL for ELISA . Beyond these concentrations, the samples should be diluted.