Serum Cystatin C Concentration Compared with Serum Creatinine Concentration as a Marker of Glomerular Filtration Rate / 대한신장학회잡지

ABSTRACT

BACKGROUND: Several studies have shown serum cystatin C to be a better parameter for glomerular filtration rate (GFR) than serum creatinine (sCr). It is also known to be more sensitive in detecting of early renal impairment. METHODS: Serum samples were obtained from 518 subjects with various renal functions for GFR determination and cystatin C measurement. GFRs were estimated by Modification of Diet in Renal Disease (MDRD) formula and classified 5 stages according to KDOQI CKD classification. The relationships between the levels of serum cystatin C or sCr and the stages of GFR were determined. RESULTS: The mean levels of serum cystatin C in stage 1 (normal renal function) subjects were not different in stage 2 (mild renal impairment) subjects (0.9+/-0.3 vs. 0.9+/-0.3 (mg/L), p>0.05). The mean levels of sCr in stage 1 subjects also were not different from the ones in stage 2 subjects (0.7+/-0.1 vs. 1.0+/-0.2 (mg/dL), p>0.05). The levels of cystatin C in stage 3 (moderate renal impairment) were significantly higher than those in stage 2 subjects. The difference of serum levels of cystatin C between stage 2 and stage 3 was more significant than the difference of sCr (0.9+/-0.3 vs. 1.2+/-0.6, p=0.007 1.0+/-0.2 vs. 1.3+/-0.3, p=0.02). The levels of cystatin C and sCr were increased as GFR decreased after stage 2. The correlation of cystatin C with GFR was similar to that of sCr (-0.675 vs. -0.670) CONCLUSION: Serum cystatin C is not better than sCr for detecting of early renal impairment, but, gives a good assessment of GFR change during the follow-up.