Analytical validation of a human particle-enhanced nephelometric assay for cystatin C measurement in feline serum and urine
Article first published online: 28 APR 2014
© 2014 American Society for Veterinary Clinical Pathology and European Society for Veterinary Clinical Pathology
Veterinary Clinical Pathology
Volume 43, Issue 2, pages 226–234, June 2014
How to Cite
Ghys, L. F. E., Meyer, E., Paepe, D., Delanghe, J. and Daminet, S. (2014), Analytical validation of a human particle-enhanced nephelometric assay for cystatin C measurement in feline serum and urine. Veterinary Clinical Pathology, 43: 226–234. doi: 10.1111/vcp.12144
- Issue published online: 3 JUN 2014
- Article first published online: 28 APR 2014
- institute for the promotion of innovation by science and technology in Flanders
- chronic kidney disease;
- Western blot analysis
In people and dogs, Cystatin C (CysC), a renal glomerular and tubular marker, seems superior to serum creatinine to estimate the glomerular filtration rate (GFR). A particle-enhanced nephelometric immunoassay is available to measure human CysC, but there are no reports in cats.
The goal of this study was the validation of the human CysC nephelometric assay with feline serum and urine, and to perform a pilot study comparing serum and urine CysC between healthy cats and cats with chronic kidney disease (CKD).
Western blot analysis was used to assess cross-reactivity between the polyclonal rabbit anti-human CysC antibody and feline CysC. Imprecision and linearity were determined for feline serum and urine CysC. Serum and urine CysC were measured in 10 healthy and 10 CKD cats.
Cross-reactivity between the polyclonal rabbit anti-human CysC antibody and feline CysC was demonstrated. Intra- and inter-assay coefficients of variation in feline serum and urine were 1.3% and 0.4%, and 12.5%, and 4.1%, respectively. Cats with CKD had a significantly higher serum CysC concentration (1.24 [0.63–2.99] vs 0.79 [0.43–1.05] mg/L; P = .02) and urine CysC/urinary Creatinine (uCr) ratio (565.6 [0–1311] vs < 0.049/uCr mg/mol; P = .005) compared with healthy cats.
The human nephelometric assay showed satisfactory validation results for feline CysC. Cats with CKD had a significantly higher sCysC concentration and uCysC/uCr ratio compared with healthy cats. Additional studies are necessary to evaluate CysC as an early marker of renal damage in cats.