[Evaluation of renal function in chronic renal disease with special reference to creatinine]

Creatinine clearance (Ccr) has been used to evaluate glomerular filtration rate (GFR) in patients with various kinds and grade of renal disease. It is quite useful in terms of simplicity, accuracy and convenience in clinical medicine. However, for the purpose of clinical research, it is not adequate to assess GFR, since a significant quantity of creatinine is secreted in the renal tubule. The secretion rate is rather increased in the endstage chronic renal disease, misleading the true GFR. It also induces an error to calculate the progression rate of a patient with chronic renal failure or to evaluate the effect of the drugs or diet therapy. Therefore, some other indices should be, in future, investigated in order to establish the quantitative evaluation of GFR in patients with chronic renal failure in stead of Ccr or serum creatinine.