CRP and COVID-19: Analysis of biochemical markers of inflammation such as CRP, ferritin, and D-dimer showed that CRP plasma levels were significantly higher in MIS-C (148 mg/L) than in COVID-19 children (13.85 mg/L) (p = 0.0051; Table 1), while ferritin and D-dimer levels were usually higher in MIS-C than in COVID-19, although the difference was not statistically significant (Table 1).