Serum Cystatin C As A Marker For Detection Of Rernal Disfunction In Patients With Chronic Kidney Disease

Objective:To explore the correlation between cystatin C(Cys C) levels and serum creatinine(Scr),creatinine clearance rate(Ccr) in different periods of renal function in patients with chronic kidney disease(CKD). To evaluate the applicability of serum Cys C as a endogenous marker for glomerular filtration rate(GFR), and attempt to apply the Cys C as a primary indicator for staging of renal function in patients with CKD. Methods:The disease group were obtained from 232 cases with CKD, collected from March in 2010 to December in 2010 among our hospitalized patient. The control group is 47 cases of healthy from medical center. Serum Cys C concentration was determined by particle enhanced turbidimetric immunoassay (PETIA), Scr by alkaline trinitrophenal method and Ccr were measured for every patient. The disease group was divided into 4 phases by Ccr. The correlation between Cys C and Scr,Ccr were compared. The area under the Receiver Operating Characteristic(ROC) curve was used for evaluating the sensitivity and specificity of Cys C and Scr for GFR decline.95% CI of Cys C in different phases were calculated. Results:The different of Scr,Ccr had no statistical significance between the phases of Ccr was higher than 80ml/min and the healthy control group, but There were great significant differences in Cys C concentrations between the two groups, in this group serum Cys C anomaly detection rate is 46.2%, the abnormal was only 17.3% by Scr. The sensitivity of Cys C was better than Scr in patients with mild to moderate kidney dysfunction. Correlation analysis indicated that Cys C was negatively related to Ccr (r=-0.812, P<0.01) and positively related to Scr (r=0.888,P<0.01).Areas under the ROC curve were 0.942 for Cys C,0.908 for Scr, the area under the ROC curve was statistically different between serum Cys C and Scr(P<0.05). The 95% CI of Cys C were 1.009-1.179,1.556-1.752,2.060-2.356 and 4.420-4.916 of the normal. Conclusion: Serum Cys C determination is an accurate and reliable parameter of GFR in patients with impaired renal function. Serum Cys C can reflect accurately the GFR to patients with kidney disease in the different period of renal damage. Cys C can be used as a primary indicator for staging in renal damaged patients.