When comparing the groups with COVID-19+ and asymptomatic COVID-19, the significance of the parameters was identified for TBARs (AUC 0.687; p = 0.051), AGEs (AUC 0.735; p = 0.0004), 8-OHdG (AUC 0.648; p = 0.050), TAS (AUC 0.709; p = 0.020), SOD (AUC 0.760; p < 0.0001), GSH/GSSG (AUC 0.658; p = 0.039), GPx (AUC 0.774; p < 0.0001), GSTpi (AUC 0.864; p < 0.001), and GR (AUC 0.871; p < 0.0001) (Table 5, Figure 4). Here, GSR is linked to COVID-19.