To differentiate the desired erythropoietic effect of roxadustat from potentially harmful polycythemia in post-transplant anemia, clinical monitoring should combine target Hb ranges with hemoglobin velocity and interruption–rechallenge rules: Target range: Maintain Hb 10–12 g/dL in adults, consistent with regulatory labeling and Phase 3 practice patterns [25,26,50]. The gene discussed is GSTM1; the disease is anemia (phenotype).