Increased urinary cystatin C reflects structural and functional renal tubular impairment independent of glomerular filtration rate

Clin Biochem. 2007 Sep;40(13-14):946-51. doi: 10.1016/j.clinbiochem.2007.04.013. Epub 2007 Apr 27.


Objectives: The ratio of the urinary mass concentrations of cystatin C and creatinine (UcysC/Ucrea)>/=11.3 mg/mmol has recently been proposed as an accurate marker for the detection of GFR</=60 mL/min/1.73 m(2).

Design and methods: We prospectively evaluated the diagnostic performance of UcysC/Ucrea>/=11.3 mg/mmol and factors associated with increased UcysC/Ucrea in 72 children and adults with a wide variety of renal disorders. UcysC/Ucrea was calculated, and GFR wad estimated from serum creatinine and cystatin C by equations.

Results: UcysC/Ucrea>/=11.3 mg/mmol had a low diagnostic value to detect GFR values</=60 mL/min/1.73 m(2) estimated by creatinine or cystatin-C-based equations with sensitivities of 72% and 63%, and specificities of 42% and 34%. ROC curves for UcysC/Ucrea to detect GFR</=60 mL/min/1.73 m(2) confirmed this with AUCs of 0.59 for creatinine and 0.57 for cystatin-C-based equations. Multivariate analysis identified tubular proteinuria, tubulointerstitial disease and heavy proteinuria, but not GFR</=60 mL/min/1.73 m(2), as factors independently associated with increased UcysC/Ucrea.

Conclusions: UcysC/Ucrea>/=11.3 mg/mmol is not an accurate marker to detect GFR</=60 mL/min/1.73 m(2), but reflects tubular dysfunction and proteinuria due to heavy proteinuria and tubulointerstitial disease.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Child
  • Child, Preschool
  • Creatinine / urine
  • Cystatin C
  • Cystatins / urine*
  • Female
  • Glomerular Filtration Rate*
  • Humans
  • Kidney Diseases / physiopathology
  • Kidney Diseases / urine*
  • Kidney Tubules / pathology
  • Kidney Tubules / physiopathology
  • Male
  • Middle Aged
  • ROC Curve


  • CST3 protein, human
  • Cystatin C
  • Cystatins
  • Creatinine