Biomarkers for chronic kidney disease in dogs: a comparison study.

The aim of this study was to determine whether serum symmetric dimethylarginine (SDMA) and cystatin C (CysC) levels can be utilized as more accurate markers of early kidney dysfunction in dogs. Forty-one client-owned dogs with chronic kidney disease (CKD), which were clinically stable, and ten beagles as healthy controls were included. All dogs underwent physical examination, systemic blood pressure measurement, complete blood cell count, and plasma biochemistry analyses. Frozen serum was used for SDMA and CysC analyses. Data analysis was performed using Kruskal Wallis, Pearson's correlation, Bland-Altman plots, and receiver operating characteristic curve. SDMA and CysC levels were significantly higher in patients with CKD at various International Renal Interest Society (IRIS) stages than in the healthy controls. In particular, CysC level was the only biomarker that could indicate the earliest stage of CKD (IRIS stage I). Similar to these results, CysC level showed better sensitivity and specificity compared to the other biomarkers in early CKD dogs.