2015 ACVIM Forum Research Abstract Program

A commercially available competitive ELISA assay for 5-HIAA was validated using acidified canine urine as the sample matrix. Validation included determination of sensitivity, dynamic range, and accuracy via spiking recovery, dilutional parallelism, and assessment of inter-and intra-assay precision. Urine samples from 33 dogs were collected, 20 clinically healthy and 13 showing signs of gastrointestinal disease. Per the manufacturer's guidelines, the samples were acidified with 6M HCl to a pH ≤3.0, and methylated prior to quantification using the ELISA assay. We observed a significant matrix effect from pooled canine urine, dilution studies showed this effect was overcome when using a 1:8 dilution of samples. Urinary creatinine concentrations were determined by the Oregon State University Veterinary Diagnostic Lab using non-acidifed aliquots. A preliminary reference range for urine 5-HIAA was derived from the central 95 th percentile for urinary 5-HIAA:Creatinine in the clinically healthy dogs.