They demonstrated that dialysis patients had lower HbA1c values than that of those without CKD with the same average glucose level, suggesting that HbA1c underestimates the glucose level in dialysis patients.[40] The authors further showed that this underestimation might be secondary to the use of erythropoietin – a larger proportion of circulating erythrocytes in EPO treated patients are younger that have not been around for long enough for sufficient glycoysylation of hemoglobin. The gene discussed is EPO; the disease is chronic kidney disease.