title: Comparison between creatinine and cystatin C-based GFR equations in renal transplantation.
abstract: BACKGROUND
  Estimation of glomerular filtration rate (GFR) from serum creatinine (Scr) or cystatin C (Cys C) exhibit variable performances.
  
  
  METHODS
  We compared the performances of 14 Scr and 9 Cys C estimated GFR equations using inulin clearance (Clin) as the reference test in 103 stable renal transplant populations. Bias, precision, receiving operation characteristics (ROC), accuracy within 30% ranges from the reference method and agreements of each test were compared.
  
  
  RESULTS
  Mean Clin was 46.4+/-20.9 ml/min/1.73 m2. Scr and Cys C levels correlated well with each other (r=0.83, P<0.0001) and with Clin (r=-0.57 and -0.53, P<0.001, respectively). ROC analysis demonstrated no superiority of Cys C over Scr. Gats equation achieved the highest accuracy of 70% in patients with GFR>or=60 ml/min/1.73 m2. In patients with GFR>or=60 ml/min/1.73 m2, the Nankivell equation demonstrated the highest accuracy of 73.91%. Cys C-based equations were not depicted to be thoroughly accurate. Bias, precision and agreement were otherwise similar in all GFR tests.
  
  
  CONCLUSIONS
  Scr-based equations did not appear to be inferior to Cys C-based equations as a means to estimate GFR in renal transplant patients.
authors.affiliation: Department of Medicine, Division of Nephrology, Royal University Hospital, University of Saskatchewan, Saskatoon, SK S7M 0Z9, Canada.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Zahran
authors.forename: Mabood
authors.initials: M
authors.lastname: Qureshi
authors.forename: Ahmed
authors.initials: A
authors.lastname: Shoker
mesh_terms: D000369:Aged, 80 and over; D003404:Creatinine / Q000097:blood*; D055316:Cystatin C; D015891:Cystatins / Q000097:blood*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007444:Inulin / Q000378:metabolism; D016030:Kidney Transplantation; D008297:Male; D008954:Models, Biological; D012372:ROC Curve
chemical_list: C525030:CST3 protein, human; D055316:Cystatin C; D015891:Cystatins; D007444:Inulin; D003404:Creatinine