Quantitative Determination of Anti-SARS-CoV-2 Spike Protein Antibodies

Quantitative determination of pan-immunoglobulin to RBD of SARS-CoV-2 spike protein was achieved via automated electrochemiluminescence immunoassay using a Roche Elecsys anti-SARS-CoV-2 S (Roche Diagnostics, Basel, Switzerland; hereafter called Roche S). As previously described, the assay was performed on a Roche Cobas e601 system (Roche Diagnostics) and used plasma or serum from vaccinated volunteers for measurement [11 (link)]. This assay has a measuring range of 0.40 to 250 U/mL (up to 2500 U/mL with on-board 1:10 dilution). A concentration of <0.80 U/mL was considered negative and ≥0.80 U/mL was considered positive [12 (link)].