Cystatin C improves the detection of mild renal dysfunction in older patients

Ann Clin Biochem. 2003 Nov;40(Pt 6):648-55. doi: 10.1258/000456303770367243.


Background: Conventional estimates of glomerular dysfunction, including serum creatinine and creatinine clearance, are inadequate in older people. In this study we have compared the diagnostic accuracy of a novel test of kidney disease, cystatin C, against these markers in older patients with a range of renal function.

Methods: Fifty-three patients (mean age 79.6 years, range 69-92 years) with a variety of medical diagnoses were recruited via outpatient clinics. Exclusion criteria included active rheumatoid disease, known current malignancy, renal replacement therapy/renal transplantation and cognitive impairment. (51)Cr-EDTA was used as the reference method against which the other markers of glomerular filtration rate were compared using regression analyses.

Results: The best fit with glomerular filtration rate was given by Cockcroft and Gault calculated clearance (R(2) = 0.83), followed by serum cystatin C (R(2) = 0.79), serum creatinine (R(2) = 0.76) and creatinine clearance (R(2) = 0.73). The accuracy for glomerular filtration rate prediction was poor for all markers. Serum cystatin C detected nearly all patients with mild renal impairment whereas serum creatinine only detected half of these cases. Regression modelling predicted that the upper limit of normal for serum cystatin C would be exceeded as glomerular filtration rate fell below 64 mL/min/1.73 m(2), compared with 44 mL/min/1.73 m(2) for serum creatinine.

Conclusion: Serum cystatin C is a simple and sensitive screening test for kidney dysfunction in older people.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Biomarkers / blood
  • Cross-Sectional Studies
  • Cystatin C
  • Cystatins / blood*
  • Edetic Acid
  • European Continental Ancestry Group
  • Female
  • Glomerular Filtration Rate
  • Humans
  • Kidney Diseases / blood*
  • Kidney Diseases / diagnosis*
  • Kidney Diseases / physiopathology
  • Male
  • Reference Values
  • Sensitivity and Specificity


  • Biomarkers
  • CST3 protein, human
  • Cystatin C
  • Cystatins
  • Edetic Acid