Korean J Nephrol.  2006 Sep;25(5):737-744.

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

• Han KH
• Han SY
• Kang YS
• Cha DR

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.

Keyword

Cystatin C; Creatinine; GFR