Value of Serum Cystatin C in Evaluating Glomerular Filtration Rate in Patients with Chronic Kidney Disease

Objective:To assess the value of serum Cystatin C(Cyst C) in evaluating glomerular filtration rate in patients with chronic kidney disease(CKD).Methods:Seventy-six hospitalized CKD patients were observed,and the data such as serum cyst C,serum creatinine (Scr) and 99m Tc-GFR were measured.The estimated GFR was calculated by the equation from the Modification of Diet in Renal Disease Study(M-GFR) and Cockcroft-Gault formula(C-GFR).99mTc-GFR was considered to be a gold standard in evaluating GFR.The correlation between the above four parameters and 99m Tc-GFR was analyzed in every group.The sensitivity and specificity were calculated,too.Results:There were significant correlation between 99m Tc-GFR and Cyst C,Scr,C-GFR and M-GFR,and the pearson coefficient were -0.81,-0.73,0.90,0.89,respectively (all P0.01).There were significant negative correlation between 99m Tc-GFR and Cyst C in CKD stage 1-3 patients,and the pearson coefficient were-0.57(P0.05),-0.44(P0.05),-0.74(P0.01),respectively.But there were no significant correlation between 99m Tc-GFR and Cyst C in stage 4-5 patients (the pearson coefficient was -0.30,P0.05).Only in stage 3 patients,there were significant correlation between Scr,C-GFR,M-GFR and 99m Tc-GFR.The sensitivity and specificity of Cyst C were higher than C-GFR and M-GFR in all stages of CKD patients,especially in stage 1CKD patients.Conclusion:Serum cystatin C is a sensible index in evaluating renal function in patients with chronic kidney disease,especially in early chronic kidney disease.