Validation of immunoassays for the candidate renal markers C-reactive protein, immunoglobulin G, thromboxane B2 and retinol binding protein in canine urine

The study of early markers for glomerular and tubular dysfunction in dogs with renal diseases holds promise to gain new insights in the pathogenesis of canine nephropathies. However, the validation of such markers in canine urine is largely lacking. Therefore, immunoassays for the quantification of a set of four urinary markers, C-reactive protein (CRP), immunoglobulin G (IgG), thromboxane B2 (TXB2) and retinol binding protein (RBP), were validated by determining their sensitivity, reproducibility, precision and accuracy in a large patient group. The results show that the immunoassays are appropriate for analysis of urinary CRP, IgG, TXB2 and RBP in dogs. Furthermore, the significant differences in urinary concentrations of the selected glomerular and tubular markers between healthy (H) dogs and dogs with several types of nephropathies (R) support their future application in both clinical settings and research models.