title: Serum cystatin C level as a potentially good marker for impaired kidney function.
abstract: OBJECTIVE
  To evaluate the diagnostic significance of serum cystatin C levels in clinical practice.
  
  
  METHODS
  Serum (99m)Tc-DTPA clearance was compared with serum cystatin C, creatinine, beta(2)-microglobulin levels and creatinine clearance in a group of patients aged 42.61 +/- 7.55 years with glomerular filtration rates of 10-60 mL/min/1.73 m(2) (n = 52) and healthy controls aged 43.90 +/- 12.06 years (n = 52).
  
  
  RESULTS
  No effect of sex on serum cystatin C levels was observed, but average levels increased with age. No significant difference was evident between the mean cystatin C levels of three blood samples taken at 1 month intervals from healthy subjects. Reference clearance was correlated with creatinine clearance (r = 0.957), cystatin C (r = 0.828), beta(2)-microglobulin (r = 0.767) and creatinine (r = 0.682). 60 mL/min/1.73 m(2) was chosen as the borderline for receiver-operating characteristics analysis. The values for the cut-off point, sensitivity, specificity and the area under curve were determined for cystatin C as 1.36 mg/L, 98%, 99% and 0.99 +/- 00.1, respectively; for creatinine, the values were 103 micromol/L, 80%, 100% and 0.97 +/- 0.01, respectively, and for beta(2)-microglobulin, the values were 2.51 mg/L, 86%, 92% and 0.94 +/- 0.02, respectively.
  
  
  CONCLUSIONS
  Serum cystatin C level can be used as a marker for renal damage.
authors: Department of Biochemistry, Cerrahpasa Medicine Faculty, Istanbul University, Cerrahpasa Tip Fakültesi, Temel Bilimler-Biokimya Anabilim Dali, 34303 Cerrahpasa-Istanbul, Turkey. huzun59@hotmail.com
authors: Hafize
authors: H
authors: Uzun
authors: Melek
authors: M
authors: Ozmen Keles
authors: Rezzan
authors: R
authors: Ataman
authors: Seval
authors: S
authors: Aydin
authors: Betül
authors: B
authors: Kalender
authors: Ezel
authors: E
authors: Uslu
authors: Gönül
authors: G
authors: Simsek
authors: Metin
authors: M
authors: Halac
authors: Safiye
authors: S
authors: Kaya
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D003404:Creatinine / Q000097:blood; D055316:Cystatin C; D015891:Cystatins / Q000097:blood*; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology; D006801:Humans; D007668:Kidney / Q000503:physiopathology*; D007674:Kidney Diseases / Q000097:blood* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012727:Sex Characteristics; D018709:Statistics, Nonparametric; D016284:Technetium Tc 99m Pentetate
chemical_list: D015415:Biomarkers; C525030:CST3 protein, human; D055316:Cystatin C; D015891:Cystatins; D003404:Creatinine; D016284:Technetium Tc 99m Pentetate