title: Urine cystatin C as a biomarker of proximal tubular function immediately after kidney transplantation.
abstract: OBJECTIVE
  Clinical methods to predict allograft function soon after kidney transplantation are ineffective.
  
  
  METHODS
  We analyzed urine cystatin C (CyC) in a prospective multicenter observational cohort study of deceased-donor kidney transplants to determine its peritransplant excretion pattern, utility for predicting delayed graft function (DGF) and association with 3-month graft function. Serial urine samples were collected for 2 days following transplant and analyzed blindly for CyC. We defined DGF as any hemodialysis in the first week after transplant, slow graft function (SGF) as a serum creatinine reduction < 70% by the first week and immediate graft function (IGF) as a reduction ≥ 70%.
  
  
  RESULTS
  Of 91 recipients, 33 had DGF, 34 had SGF and 24 had IGF. Urine CyC/urine creatinine was highest in DGF for all time-points. The area under the curve (95% CI) for predicting DGF at 6 h was 0.69 (0.57-0.81) for urine CyC, 0.74 (0.62-0.86) for urine CyC/urine creatinine and 0.60 (0.45-0.75) for percent change in urine CyC. On the first postoperative day, urine CyC/urine creatinine and percent change in urine CyC were associated with 3-month graft function.
  
  
  CONCLUSIONS
  Urine CyC on the day after transplant differs between degrees of perioperative graft function and modestly corresponds with 3-month function.
authors.affiliation: Department of Medicine, Section of Nephrology, Yale University School of Medicine and the Clinical Epidemiology Research Center, VAMC, New Haven, CT 06516, USA.
authors.forename: Isaac E
authors.initials: IE
authors.lastname: Hall
authors.forename: Jay L
authors.initials: JL
authors.lastname: Koyner
authors.forename: Mona D
authors.initials: MD
authors.lastname: Doshi
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Marcus
authors.forename: Chirag R
authors.initials: CR
authors.lastname: Parikh
mesh_terms: D000328:Adult; D015331:Cohort Studies; D003404:Creatinine / Q000378:metabolism; D055316:Cystatin C / Q000652:urine*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007668:Kidney / Q000473:pathology; D016030:Kidney Transplantation / Q000009:adverse effects / Q000379:methods*; D007684:Kidney Tubules / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009391:Nephelometry and Turbidimetry / Q000379:methods; D011446:Prospective Studies; D006435:Renal Dialysis
chemical_list: D055316:Cystatin C; D003404:Creatinine