Evaluation of Biological Variance of Cystatin C in Comparison With Other Endogenous Markers of Glomerular Filtration Rate in Healthy Dogs

Abstract

Background: The aim of the study was to investigate and compare components of variance of endogenous markers of glomerular filtration rate (GFR) in healthy dogs and impact on the interpretation of results.Hypothesis: Cystatin C (cysC) in the dog is superior to creatinine (crea) and urea in detecting decreased renal function because of a high index of individuality (IoI).Animals and Method: Variance components of cysC, crea (2 methods: crea E , crea J ), urea, and inorganic phosphate (Pi) in plasma were determined in a longitudinal study over 6 months in 24 healthy dogs (6 German Shorthair Pointers, 18 Beagles). IoI and critical differences (C D ) were calculated, as well as the numbers of measurements necessary to determine the individual's homeostatic set point.Results: Mean concentrations of cysC, crea J , crea E , urea, and Pi (mean 6 SD) were 0.93 6 0.19 mg/L, 0.94 6 0.17 mg/dL, 0.76 6 0.18 mg/dL, 35.34 6 9.08 mg/dL, and 3.74 6 0.68 mg/dL, respectively. The IoI for cysC, crea J , crea E , urea, and Pi were 0.96, 0.89, 0.80, 0.90, and 1.16, respectively. The C D for cysC, crea J , crea E , urea, and Pi were 0.37 mg/L, 0.26 mg/dL, 0.27 mg/dL, 16.94 mg/dL, and 1.45 mg/dL, respectively.Conclusion: In dogs, components of biological variance of cysC and crea are in the same range. Analytical precision requirements were fulfilled by crea both , urea, and Pi. All parameters had an intermediate IoI, which allowed the application of population-based reference limits. The application of the C D for crea or cysC might be useful in detecting a decrease of GFR, when sequential measurements in an individual reveal an increase exceeding the C D but not the upper reference limit.

Evaluation of the Measurement of Serum Cystatin C by an Enzyme-Linked Immunosorbent Assay for Humans as a Marker of the Glomerular Filtration Rate in Dogs

“…In previous veterinary reports, a polyethylene PETIA was shown to reliably measure canine serum Cys-C [2,6,15,20,28]. Almy et al [2] showed that Western blot analysis demonstrated considerable cross-reactivity of the rabbit polyclonal anti-human Cys-C antibody with canine Cys-C.…”

“…In previous reports, the serum Cys-C concentration in dogs was measured by polystyrene PETIA [2,6,15,20,28]. However, it is difficult to use the polystyrene PETIA method for the measurement of canine serum Cys-C concentration in Japan, because this method is unavailable in Japanese commercial laboratories.…”

Conceitos E Aplicabilidade Dos Principais Biomarcadores Na Nefrologia Veterinária – Revisão De Literatura

“…A depuração de creatinina endógena é uma das mais utilizadas apesar de não ser um procedimento simples (TRALL et al 2015). Para a realização da depuração ou cleareance de creatinina, deve-se mensurar tanto a creatinina sérica quanto a urinária; pode ser usado o método colorimétrico, que é um teste cinético baseado na reação de creatinina com picrato alcalino (HALL et al 2014) ou o enzimático que mensura tanto a creatinina quanto a ureia no soro sanguíneo de humanos e animais (PAGITZ et al 2007). Com a finalidade de estimar a taxa de filtração glomerular (TFG), pode-se mensurar o clearance de creatinina (Ccr) em período de 24 horas.…”

“…De acordo com Pagitz et al (2007) a cistatina C pode ser mensurada tanto no soro quanto na urina de humanos e nos de cães, através do ensaio comercial de imunoturbidimetria de partículas; e atualmente o imunoensaio de nefelometria reforçada (PENIA) está sendo utilizado no soro e urina de humanos, porém devido ao seu alto custo esse método ainda não é utilizado na veterinária (GHYS et al 2014).…”

Urinary biomarkers of renal function in dogs and cats: a review

“…In dogs, serum cystatin C may be an alternative to serum creatinine for screening dogs with decreased GFR due to chronic renal failure (Almy et al 2002). Nevertheless, Pagitz et al (2007) showed that the biological variance of cystatin C and creatinine in the serum of dogs is similar.…”