title: Cystatin C in acute kidney injury.
abstract: OBJECTIVE
  This review will summarize and discuss the role of cystatin C in the diagnosis of acute kidney injury.
  
  
  RESULTS
  Cystatin C is easily measured and has the characteristics of an ideal marker of kidney function. Data suggest that cystatin C is modified by age, sex, muscle mass, obesity, smoking status, thyroid function, inflammation, and malignancy. These factors suggest the need for age-specific and sex-specific reference standards. Cystatin C-based glomerular filtration rate estimates may perform better than creatinine in selected patient populations (elderly, children, transplantation, cirrhosis, malnourished). Cystatin C has been evaluated for the early diagnosis of acute kidney injury (AKI) in several populations. Serum cystatin C has value for the diagnosis of acute kidney injury; however, it has often performed similarly to creatinine. Urinary cystatin C has potential as an early marker.
  
  
  CONCLUSIONS
  Cystatin C is an accurate biomarker for the early detection of AKI, and may, in selected populations, be superior to creatinine; however, data have been inconsistent. It also has reasonable discrimination for important outcomes such as death and renal replacement therapy (RRT). Additional studies are needed that focus on the cost-effectiveness of earlier detection of AKI with cystatin C compared with creatinine, and whether these biomarkers have complementary value.
authors.affiliation: Division of Critical Care Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada. bagshaw@ualberta.ca
authors.forename: Sean M
authors.initials: SM
authors.lastname: Bagshaw
authors.forename: Rinaldo
authors.initials: R
authors.lastname: Bellomo
mesh_terms: D058186:Acute Kidney Injury / Q000097:blood* / Q000175:diagnosis*; D000367:Age Factors; D015415:Biomarkers; D006348:Cardiac Surgical Procedures / Q000009:adverse effects; D016638:Critical Illness; D055316:Cystatin C / Q000097:blood / Q000378:metabolism*; D005919:Glomerular Filtration Rate; D006530:Hepatorenal Syndrome / Q000175:diagnosis; D006801:Humans; D007677:Kidney Function Tests; D011183:Postoperative Complications / Q000175:diagnosis; D012680:Sensitivity and Specificity; D012737:Sex Factors
chemical_list: D015415:Biomarkers; D055316:Cystatin C