Serum Cystatin C as a Marker for Detection of Early Renal Disfunction in Patients with Chronic Kidney Disease

Objective:To evaluate the applicability of serum cystatin C as a endogenous marker for detection of early renal disfunction in patients with chronic kidney disease.Methods:Serum samples were obtained from 88 cases with chronic kidney disease,collected from July in 2005 to February in 2006 among our hospitalized patient.Serum cystatin C concentration was determined by particle-enhanced turbidimetric immunoassay(PETIA),Serum creatinine(Scr)by alkaline trinitrophenal method and Creatinine clearance rate(Ccr)were measured for every patient.Meanwhile,glomerular filtration rate(GFR)measure by 99m Tc-DTPA clearance was considered to be a Gold Standard,the correlation between GFR and the above three parameters were compared,the area under the Receiver Operating Characteristic curve(AUCROC)and the likelihood ratio(LR)were used for evaluating the reliability of cystatin C.Results:The significant correlation were found between GFR and cystatin C、Scr、Ccr,and that of between GFR and cystatin C was the most strongest.The AUCROC for cystatin C、Scr 、Ccr was 0.980、0.914、0.941 respectively,and there was significant statistical difference between cystatin C and Scr(P0.05),but no statistical difference between cystatin C and Ccr(P0.05).LR of serum cystatin C was the best among the above three parameters.Conclusion:Serum cystatin C determination is an accurate and reliable parameter of GFR.It can be a better endogenous marker for detection of early renal disfunction in patients with chronic kidney disease than serum creatinine and Ccr.