HbA1c is regarded as mean glucose and does not reflect acute fluctuation in glucose level.24 The contribution of fasting or postprandial glucose varies with different HbA1c levels while postprandial glucose contributed more at lower HbA1c levels.25,26 HbA1c is also affected by test time,24 elevated blood urea nitrogen level, metabolic acidosis, anemia, blood transfusion, hemoglobinopathies, erythropoietin-stimulating agents, and protein-energy wasting,27 which might occur in CKD patients. This evidence concerns the gene EPO and chronic kidney disease.