Seven SARS-CoV-2 IgG assays (Abbott SARS-CoV-2 IgG, Wiesbaden, Germany; DiaSorin Liaison® SARS-CoV-2 S1/2 IgG, DiaSorin, Dietzenbach, Germany; Epitope EDI™ Novel Coronavirus COVID-19 IgG ELISA Kit, Epitope Diagnostics, San Diego, CA, USA; Euroimmun Anti-SARS-CoV-2 ELISA (IgG), EUROIMMUN AG, Lübeck, Germany; Mikrogen recomWell SARS-CoV-2 IgG, Mikrogen GmbH, Neuried, Germany; SARS-CoV-2 ViraChip® IgG Test, Viramed Biotech AG, Planegg, Germany; and SERION ELISA agile SARS-COV-2 IgG, Institute Virion-Serion GmbH, Würzburg, Germany), as well as one total SARS-CoV-2 antibody test (Roche Elecsys Anti-SARS-CoV-2, Roche Diagnostics, Mannheim, Germany), were included in this study. The recombinant antigens of these tests cover the N protein (Abbott, Epitope, Mikrogen, Roche) and the entire S protein (Virion-Serion), as well as its S1 domain alone (Euroimmun) or together with the S2 domain (DiaSorin). The SARS-CoV-2 ViraChip® IgG test kit uses the purified viral surface antigens S1 and S2 and the N antigen, which are all presented separately at a defined position on a nitrocellulose film (Table S1).