Study validates canine urine 5-HIAA ELISA against LC-MS/MS

A BSAVA PetSavers-funded study published in the Journal of Small Animal Practice validated a commercially available ELISA for measuring urinary 5-hydroxyindole acetic acid, or 5-HIAA, in dogs, comparing it with liquid chromatography-tandem mass spectrometry, the reference method. The Cambridge team, led by Daniel Castillo and colleagues, reported acceptable assay precision and good overall agreement with LC-MS/MS, with a small mean bias, but noted that performance at higher concentrations still needs more validation before the test is used broadly in clinical decision-making. BSAVA says the work could make urinary 5-HIAA testing more accessible and lower cost for clinicians, especially because serotonin itself has a very short serum half-life and 5-HIAA is considered a more practical urinary marker. (bsava.com)

Why it matters: For veterinary professionals, this is less about a new disease marker than about assay practicality. Serotonin signaling has been implicated in several canine conditions, including myxomatous mitral valve disease, pulmonary hypertension, and dilated cardiomyopathy, but reference testing by mass spectrometry is expensive and not widely available. A usable ELISA could widen access to urinary 5-HIAA measurement in practice or through more routine laboratory workflows, although the study’s caution around high-end concentrations means results will likely need careful interpretation, and perhaps confirmation by reference methods, in dogs with marked abnormalities. That caution fits a broader pattern in veterinary biomarker work, where urine matrix effects can complicate ELISA performance and make species-specific validation essential. (bsava.com)

What to watch: The next step is whether follow-on studies establish clinical cutoffs, reference intervals, and real-world performance in dogs with suspected serotonin-linked disease, particularly at higher urinary 5-HIAA concentrations. (synapsesocial.com)