Previous studies in concordance with this study revealed that RET-He could be used as an alternative parameter for diagnosing iron deficiency anemia in regular dialysis-dependent patients.26, 27, 28, 29, 30 when Early dose adjustment to reduce the risks associated with inappropriately high doses of EPO was calculated using RET-He (ESA UI/kg/RET-He) in the current cohort instead of the classic calculation using hemoglobin concentration (ESA UI/kg/Hb), there was a statistically significant positive correlation with the ERI (r = 0.84; p-value = 0.001). This evidence concerns the gene GSTM1 and anemia.