Serum cystatin-C: a sensitive marker for early detection of reduction in glomerular fitration rate

ABSTRACT

The aim of the present study was to evaluate the diagnostic value of serum cystatin-C [Cys-C] as a serum marker of glomerular filtration rate [GFR] in patients with various renal diseases with a wide range of renal function as well as to compare between serum Cys-C, creatinine and beta 2-microglobulin [beta 2m] as indicators of GFR. The study included 63 patients [39 males and 24 females aged between 17 and 75 years]. Serum Cys-C was measured by automated particle- enhanced turbidimetry, serum creatinine by Synchron CX-7 autoanalyzer, serum beta 2m by enzymognost beta 2m assay and GFR by 99m Tc-labeled diethylenetriamine pentaacetic acid [99m TcDTPA] clearance. The results demonstrated that serum Cys-C significantly increased in patients with reduced GFR [less than 80ml/min], while serum creatinine and serum beta 2m were significantly increased at a later stage of renal insufficiency at GFR [less than 40ml/min]. The sensitivity and diagnostic accuracy of Cys-C were better than that of serum creatinine and beta 2m