GSTM1 and COVID-19: Compared to healthy controls, hematocrit (35.9 ± 7.38 vs 42.0 ± 2.62: %, p = 0.0043; Figure 1B), Hb concentration (11.6 ± 2.42 vs 14.1 ± 0.93: g/dL, p = 0.0012; Figure 1C), MCV (87.1 ± 6.75 vs 94.1 ± 3.94: μm3, p = 0.0012; Figure 1D), mean corpuscular hemoglobin (MCH; 28.0 ± 2.99 vs 31.7 ± 1.31: pg, p = 0.0001; Figure 1E), and MCHC (32.3 ± 1.64 vs 33.6 ± 0.41: g/dL, p = 0.0073; Figure 1F) were all lower in COVID-19 subjects, whilst RBC distribution width was higher (14.2 ± 2.08 vs 11.4 ± 0.67: %, p < 0.0001; Figure 1G).