The National Kidney Foundation Kidney Disease Outcomes Quality Initiative (NKF KDOQI) defined hypo-responsiveness to EPO as the presence of at least one of the following conditions: (1) a significant decrease in hemoglobin level at a constant EPO dose, (2) a significant increase in the EPO dose required to preserve a certain hemoglobin level, or (3) a failure to raise the hemoglobin level to >11 g/dL despite an EPO dose equivalent to EPO >500 IU/kg/week [44]. This evidence concerns the gene EPO and kidney disorder.