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Analytical validation of a human particle‐enhanced nephelometric assay for cystatin C measurement in feline serum and urine
Author(s) -
Ghys Liesbeth F. E.,
Meyer Evelyne,
Paepe Dominique,
Delanghe Joris,
Daminet Sylvie
Publication year - 2014
Publication title -
veterinary clinical pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.537
H-Index - 51
eISSN - 1939-165X
pISSN - 0275-6382
DOI - 10.1111/vcp.12144
Subject(s) - cats , urine , cystatin c , renal function , polyclonal antibodies , creatinine , medicine , urology , immunoassay , endocrinology , chemistry , antibody , immunology
Background In people and dogs, Cystatin C ( C ysC), 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. Objective 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 ). Methods 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. Results 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. Conclusions The human nephelometric assay showed satisfactory validation results for feline CysC. Cats with CKD had a significantly higher sC ysC concentration and uC ysC/uCr ratio compared with healthy cats. Additional studies are necessary to evaluate CysC as an early marker of renal damage in cats.