Study of correlation between serum cystatin C and creatinine clearance rate for evaluation of renal function in gerontal patients.

Objective:To explore the clinical significance of serum cystatine C(Cys C) for evaluation of renal function in gerontal patients.Methods:91 hospitalized patients with a mean age of 83-year old were divided into control group(without kidney disease,n=52) and kidney disease group(n=39) according to their medical records and test results.Serum cystatin C(Cys C) concentration was determined by latex enhanced turbidimetric immunoassay(PETIA).Serum creatinine(Scr),blood urea nitrogen(BUN) and urine creatinine(Ucr) were measured by enzyme methods in order to calculate the creatinine clearance rate(Ccr).All above items were compared between two groups eventually.Results:Significant differences were found in Cys C,Ccr,Scr and BUN between two groups(P0.01).Cys C method and Ccr method for determination of the damage of glomerular filtration rate(GFR) had positive rate of 29.7% and 62.6%,respectively,and their concordance rate was 28.6%(P0.01).Ccr method had a 34.1% false positive rate and Cys C was better than Ccr in determination of GFR damage.Conclusion:As an endogenous marker controlled by genes,Cys C reflect GFR more accurately and objectively than Ccr.Using this indicator to determine GFR damage is a fast,convenient and repeated method.It is superior to Ccr in evaluation of renal function.