Urine ammonia ratio may help predict outcomes in canine CKD
Bottom line
Version 1 — Brief
A new prospective observational study suggests the urine ammonia-to-creatinine ratio, or UACR, could help veterinarians identify which dogs with stable chronic kidney disease are at higher risk of faster progression and shorter survival. In the study, dogs with lower UACR values had worse outcomes, and a threshold below 2.0 was associated with more rapid disease progression over 12 months. The work builds on earlier research establishing a reference interval for UACR in healthy dogs and adds evidence that impaired urinary ammonia excretion may reflect clinically meaningful acid-base dysregulation in canine CKD. (pmc.ncbi.nlm.nih.gov)
Why it matters: For veterinary professionals, the finding points to a potentially practical, noninvasive biomarker that could complement creatinine, urine protein measurements, urine specific gravity, blood pressure, and IRIS staging when monitoring dogs with CKD. Because metabolic acidosis can contribute to poor outcomes and may not always be obvious early, UACR could eventually help flag patients who need closer follow-up or earlier consideration of alkali therapy, though the authors note that the cutoff is not yet externally validated and the test is not ready to stand alone in clinical decision-making. (pmc.ncbi.nlm.nih.gov)
What to watch: Watch for validation studies, assay standardization, and whether UACR is incorporated into future CKD monitoring or treatment guidance for dogs. (pmc.ncbi.nlm.nih.gov)
Key facts
- Study type
- Prospective observational study
- Population
- Dogs with stable chronic kidney disease
- Biomarker
- Urine ammonia-to-creatinine ratio, or UACR
- Main finding
- Lower UACR was linked to faster progression and shorter survival
- Progression definition
- >25% increase in serum creatinine over 12 months
- Risk threshold
- UACR below 2.0
- Study limitation
- Threshold was derived from the study cohort and was not externally validated
- Clinical context
- UACR is not ready to stand alone in clinical decision-making
Version 2 — Full analysis
Urinary ammonia excretion may be emerging as a useful prognostic signal in canine chronic kidney disease. A newly published study found that dogs with stable CKD and lower urine ammonia-to-creatinine ratios had shorter survival and faster disease progression, adding a new candidate biomarker to a field that has long relied on creatinine, proteinuria, urine concentrating ability, blood pressure, and clinical staging to estimate risk. (pmc.ncbi.nlm.nih.gov)
The idea didn't appear out of nowhere. Researchers had already established a reference interval for UACR in healthy dogs and reported that ammonia excretion is impaired in dogs with reduced renal function. That matters because the kidney's ability to excrete ammonia is central to acid handling, and in both veterinary and human nephrology, disrupted acid-base balance has been linked to worse outcomes. NC State's May 28, 2026, news release helped bring the latest canine findings to a broader clinical audience, and dvm360 followed on May 29, 2026, highlighting the study for practitioners. (pmc.ncbi.nlm.nih.gov)
In the new study, investigators followed dogs with stable CKD prospectively and defined progression as a greater than 25% increase in serum creatinine during the 12-month study period. According to the report, dogs with lower UACR values progressed faster and had higher mortality, with a UACR cutoff below 2.0 performing as a marker of higher risk. The authors also noted that this is the first canine dataset to evaluate UACR in this prognostic way, and that the threshold was derived from the study cohort rather than pre-specified or externally validated. (pmc.ncbi.nlm.nih.gov)
That caution is important. A promising biomarker isn't the same thing as a ready-to-deploy standard. The current evidence suggests UACR may capture a dimension of CKD biology that routine markers miss, particularly subclinical acid retention or impaired renal ammoniagenesis, but it still needs broader validation across practice settings, disease stages, diets, and laboratory methods. The earlier reference-interval work also suggested factors such as age and body size may influence interpretation, which means clinical context will matter if the test moves toward wider use. (pmc.ncbi.nlm.nih.gov)
Industry and professional coverage has framed the finding as clinically relevant because it could help identify dogs that might benefit from targeted intervention sooner. Both NC State's release and trade coverage emphasized the possibility that low UACR could flag patients for therapies aimed at metabolic acidosis, including alkali treatment, before overt deterioration becomes obvious on standard monitoring. Still, no major guideline body has yet incorporated UACR into routine CKD algorithms for dogs, so the conversation remains at the evidence-building stage rather than the standard-of-care stage. (news.ncsu.edu)
Why it matters: For veterinarians, the practical appeal is clear: urine is already part of the CKD workup, and a noninvasive prognostic marker layered onto existing monitoring could improve case stratification without adding substantial burden for the pet parent. If validated, UACR might help clinicians decide which dogs need tighter recheck intervals, earlier nutritional or acid-base interventions, or more detailed counseling about prognosis. It may be especially useful in dogs whose creatinine is relatively stable but whose renal acid excretion is already faltering. That said, UACR should be viewed as additive, not substitutive, alongside IRIS staging, proteinuria assessment, blood pressure control, and serial trend monitoring. (pmc.ncbi.nlm.nih.gov)
What to watch: The next step is external validation, ideally in larger and more diverse CKD populations, followed by work on analytical standardization and intervention studies asking the most clinically important question: whether acting on a low UACR actually changes outcomes. If those studies are positive, UACR could move from an interesting research marker to a tool that shapes how veterinary teams monitor and manage canine CKD. (pmc.ncbi.nlm.nih.gov)