Elecsys^® Anti-SARS-CoV-2 S is an immunoassay for the in vitro quantitative determination of total antibodies to the SARS-CoV-2 S protein RBD in human serum and plasma. The assay uses a recombinant RBD protein in a double-antigen sandwich assay format, which favors the quantitative determination of high affinity antibodies against SARS-CoV-2. The test is intended as an aid to assess the adaptive humoral immune response, including neutralizing antibodies, to the SARS-CoV-2 S protein after natural infection with SARS-CoV-2 or in vaccine recipients.