Evaluation of serum Cystatin C in elderly patients as a marker for renal filtration function

Objective:To study the clinical significance of serum Cystatin C in evaluation of renal filtra-tion function in elderly patients.Methods:A particle-enhanced nephelometric immunoassay(PENIA)was used to measure concentration of serum cystatin C.We determined the correlation between cystatin C and levels of serum creatinine(Scr)and creatinine clearance(Ccr)in189cases of elderly patients.Results:There was a significant positive correlation between serum cystatin C and serum creatinine level(r=0.92,P0.001).Signif-icant negative correlation was observed between serum cystatin C and logCcr(r=-0.814,P0.001).When Ccr was50~80ml/min,the abnormal rate of cystatin C(77.9%)was far higher than that of creatinine(9.1%).Conclusions:Serum cystatin C seems to be an attractive alternative and more accurate than serum creatinine for the estimation of GFR in elderly patients.