title: Initial evaluation of canine urinary cystatin C as a marker of renal tubular function.
abstract: OBJECTIVE
  To evaluate the performance of a particle-enhanced turbidimetric assay for measuring canine urinary cystatin C and to investigate if the urinary cystatin C to creatinine ratio is higher in dogs with renal disease than in non-renal disease dogs.
  
  
  METHODS
  Urinary cystatin C was measured by particle-enhanced turbidimetric assay using an avian antihuman cystatin C antibody and the performance of this assay was evaluated. Clinical relevance was tested in 46 dogs that were divided into three groups: healthy dogs (n=14), non-renal disease dogs (n=17) and dogs with renal disease (n=15).
  
  
  RESULTS
  The assay was linear (R(2)=0·99) and precise (mean intra- and inter-assay coefficients of variation were 2·3 and 2·9%, respectively). The recovery was 111·5% and the limit of blank was 0·02 mg/L. Urinary cystatin C and urinary cystatin C to creatinine ratio differed significantly (P<0·001) between the three cohorts of dogs.
  
  
  CONCLUSIONS
  Measurement of cystatin C by particle-enhanced turbidimetric assay performed with high precision and linearity. This assay can be processed on automated clinical chemistry analysers making it widely available to commercial laboratories. Urinary cystatin C to creatinine ratio can differentiate dogs with renal disease from dogs without renal disease. These preliminary results suggest that urinary cystatin C to creatinine ratio is a promising marker for evaluating renal tubular function.
authors.affiliation: Department of Veterinary Medicine, University of Cambridge, Cambridge, Cambridgeshire, UK.
authors.forename: P
authors.initials: P
authors.lastname: Monti
authors.forename: G
authors.initials: G
authors.lastname: Benchekroun
authors.forename: D
authors.initials: D
authors.lastname: Berlato
authors.forename: J
authors.initials: J
authors.lastname: Archer
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000652:urine; D016022:Case-Control Studies; D003404:Creatinine / Q000652:urine*; D055316:Cystatin C / Q000652:urine*; D004283:Dog Diseases / Q000175:diagnosis / Q000652:urine*; D004285:Dogs; D005260:Female; D007674:Kidney Diseases / Q000175:diagnosis / Q000652:urine / Q000662:veterinary*; D008297:Male; D009391:Nephelometry and Turbidimetry / Q000379:methods / Q000592:standards / Q000662:veterinary*; D015203:Reproducibility of Results
chemical_list: D015415:Biomarkers; D055316:Cystatin C; D003404:Creatinine