FCGR2A and COVID-19: To determine the diagnostic sensitivities of the two SARS-CoV-2 IgG FcγR ELISAs, 213 longitudinal serum samples obtained from 35 German patients with PCR-confirmed SARS-CoV-2 infection and 139 serum samples from healthy German blood donors (HDs), collected before the COVID-19 pandemic, were analyzed (Fig. 3).