GSTM1 and anemia (phenotype): According to the KDIGO Clinical Practice Guideline for Anemia in Chronic Kidney Disease [87], assessment of anemia in patients with CKD, regardless of age and disease stage, should include: hemogram (erythrocyte count, Hb concentration, hematocrit, hematimetric indices (mean corpuscular volume (MCV), mean hemoglobin concentration (MHC) and mean corpuscular hemoglobin concentration (MCHC)), leukocyte and platelet counts); reticulocyte count and reticulocyte maturity indices; serum iron, ferritin and transferrin saturation (TSAT); and serum levels of folate and vitamin B12.