Results (1) serum creatinine and Cystatin C inversely related to the 24h creatinine clearance and predicted GFR of Cockcrolf - Gault, serum Cystatin C is more closely related with the 24 h creatinine clearance than serum creatinine (r = - 0, 588; p < 0001 and r = - 0, 466; p < 0.001 respectively).