Detection of SARS-CoV-2 IgG/total antibodies in twelve routine samples. A signal (S)/cut-off (CO) value ≥1 is considered as positive for SARS-CoV-2 IgG/total antibodies. The samples #4 to #6 were obtained from family members of the SARS-CoV-2-infected patient no. 14 (sample #22 in Figure 1). Results of the plaque reduction neutralization test (PRNT, Figure S2), the ViraChip® IgG test (Viramed, VM), and of both recomLine assays (blot v1 and v2) are listed in the table. p, positive; n, negative; and nd, not determined. For better clarity, positive test results are printed in red in the table.