GSTM1 and COVID-19: In our study, levels of Hb, RBC, PCV, MCV, MCH, MCHC, MPV, lymphocyte%, monocyte%, eosinophil%, basophil%, and PDW were lower in patients with moderate and severe COVID-19 than in patients with mild COVID-19 where these values are closer to the normal level. Values of MCV, MCH, MCHC, MPV, basophil%, and PDW were statistically not significant; therefore, weak correlation was found.