Figure legends

Figure 1: Flowchart illustrating the study design and procedures of a prospective cross-sectional study in a real-life clinical setting (diagnostic accuracy study). Consecutive health-care workers and inpatients with suspected or possible previous COVID-19 were prospectively included. Abbreviations: ELISA, enzyme-linked immunosorbent assay; ECLIA, electrochemiluminescence immunoassay; CLIA, chemiluminescence immunoassay; LFI, lateral flow immunoassay; N, nucleoprotein; RBD, receptor binding domain of the SARS-CoV-2 spike glycoprotein; S1/2, domain 1 or 2 of the SARS-CoV-2 spike glycoprotein; RBD+, extended receptor binding domain of the SARS-CoV-2 spike glycoprotein; RT-PCR, real-time PCR.
Figure 2: Distribution of serological testing results in patients with and without previous COVID-19. IgG or pan-Ig responses against the nucleoprotein (N), the receptor binding domain of the SARS-CoV-2 spike glycoprotein (RBD), the domain 1 or 2 of the SARS-CoV-2 spike glycoprotein (S1/S2), and the extended RBD domain are shown. Consecutive health-care workers and inpatients with suspected or possible previous COVID-19 were prospectively included (n=3’658; prevalence 5.3%).
Figure 3: Accuracy of various serological tests for the identification of patients with previous COVID-19. Receiver operating characteristics (ROC) curves of IgG or pan-Ig responses against the nucleoprotein (N), the receptor binding domain of the SARS-CoV-2 spike glycoprotein (RBD), the domain 1 or 2 of the SARS-CoV-2 spike glycoprotein (S1/S2), and the extended RBD domain are shown. Consecutive health-care workers and inpatients with suspected or possible previous COVID-19 were prospectively included (n=3’658; prevalence 5.3%).
Figure 4: Antibody responses and live SARS-CoV-2 neutralization. Z-scored serological test results and serum dilutions at full neutralization are shown as determined in 201 selected individuals (non-linear curve fitting). Abbreviations: ELISA, enzyme-linked immunosorbent assay; ECLIA, electrochemiluminescence immunoassay; CLIA, chemiluminescence immunoassay; LFI, lateral flow immunoassay; N, nucleoprotein; RBD, receptor binding domain of the SARS-CoV-2 spike glycoprotein; S1/2, domain 1 or 2 of the SARS-CoV-2 spike glycoprotein; RBD+, extended receptor binding domain of the SARS-CoV-2 spike glycoprotein
Figure 5: Antibody response in salient subgroups of patients.Anti-S1 ELISA results in patients with previous COVID-19 are given. * P=0.0005; ** P<0.0001
Figure 6: Comparative diagnostic accuracy of various serological tests for (A) the identification of patients with previous COVID-19, and (B) the presence of neutralizing antibodies. Abbreviations: ELISA, enzyme-linked immunosorbent assay; ECLIA, electrochemiluminescence immunoassay; CLIA, chemiluminescence immunoassay; LFI, lateral flow immunoassay; N, nucleoprotein; RBD, receptor binding domain of the SARS-CoV-2 spike glycoprotein; S1/2, domain 1 or 2 of the SARS-CoV-2 spike glycoprotein; RBD+, extended receptor binding domain of the SARS-CoV-2 spike glycoprotein