Urine ammonia ratio shows promise in canine CKD prognosis
Bottom line
A new prospective observational study suggests the urine ammonia-to-creatinine ratio, or UACR, could help veterinarians identify dogs with chronic kidney disease that are at higher risk for faster progression and shorter survival. In the study, published in the Journal of Veterinary Internal Medicine on May 28, 2026, dogs with stable CKD and a UACR below 2.0 had significantly shorter survival times and were more likely to experience disease progression over 12 months. The work builds on earlier research that established a reference interval for canine UACR and linked lower urine ammonia excretion with worsening renal function, positioning UACR as a potential noninvasive marker of impaired acid excretion in canine CKD. (pmc.ncbi.nlm.nih.gov)
Why it matters: For veterinary professionals, the finding points to a possible way to sharpen prognosis beyond standard CKD staging alone. Current IRIS guidance for dogs focuses on creatinine and/or SDMA, then substaging by proteinuria and blood pressure; UACR is not part of those recommendations today. If validated further, it could help flag dogs with acid-base dysregulation earlier, identify patients that may benefit from closer monitoring or metabolic acidosis management, and add another practical urine-based biomarker to CKD workups. (iris-kidney.com)
What to watch: The next question is whether UACR testing becomes standardized, commercially accessible, and prospectively tied to treatment response before it moves into broader clinical use. (pmc.ncbi.nlm.nih.gov)
Key facts
- Study type
- Prospective observational study
- Species
- Dogs with stable chronic kidney disease
- Biomarker
- Urine ammonia-to-creatinine ratio, or UACR
- Key cutoff
- UACR below 2.0
- Main finding
- Dogs with UACR below 2.0 had shorter survival and were more likely to progress over 12 months
- Progression definition
- Increase in serum creatinine of more than 25% during the 12-month study period
- Publication
- Journal of Veterinary Internal Medicine
- Publication date
- May 28, 2026
- Clinical context
- UACR is not part of current IRIS CKD staging recommendations
A newly published study is putting urine ammonia excretion on the radar as a prognostic signal in canine chronic kidney disease. In JVIM, investigators reported that dogs with stable CKD and lower urine ammonia-to-creatinine ratios had faster disease progression and shorter survival, suggesting UACR may offer a noninvasive way to identify higher-risk patients earlier in the course of disease. (pmc.ncbi.nlm.nih.gov)
The finding builds on a growing line of work around ammonia handling in dogs. A 2022 study established a reference interval for canine UACR, helping define what normal urine ammonia excretion looks like in healthy dogs. More recently, researchers also reported that UACR declines as renal function worsens in dogs with CKD, reinforcing the biologic rationale that impaired renal ammonia excretion may reflect reduced acid elimination capacity as kidney disease advances. (pmc.ncbi.nlm.nih.gov)
In the new study, investigators followed dogs with stable CKD prospectively and evaluated whether impaired ammonia excretion tracked with outcomes. According to the publication abstract and related coverage, dogs with UACR below 2.0 had shorter survival and were more likely to meet the study’s definition of CKD progression, which was an increase in serum creatinine of more than 25% during the 12-month study period. The study frames low UACR as a marker of acid-base dysregulation that may emerge before overt metabolic complications are obvious on routine monitoring. (pmc.ncbi.nlm.nih.gov)
That matters because current CKD frameworks do not capture this dimension directly. IRIS staging for stable canine CKD is based on creatinine and/or SDMA, with substaging by urine protein-to-creatinine ratio and systemic blood pressure. IRIS also notes that signs of tubulopathy or acidosis can support early CKD recognition, but UACR is not currently included as a standard staging or substaging tool. In other words, this biomarker is emerging alongside, not instead of, the established CKD toolkit. (iris-kidney.com)
Public-facing university and trade coverage has emphasized the same clinical takeaway: dogs with lower urine ammonia levels may be the ones most likely to benefit from earlier targeted intervention. That’s consistent with how nephrology has evolved in both veterinary and human medicine, where clinicians increasingly look for markers that do more than confirm kidney dysfunction and instead help predict trajectory. This is an inference from the study’s framing and current CKD practice patterns, rather than a formal change in guidelines. (pmc.ncbi.nlm.nih.gov)
Why it matters: For practicing veterinarians, UACR’s appeal is that it could add prognostic value from a urine sample, potentially helping distinguish the dog with apparently stable CKD from the dog whose disease is more biologically active. That could influence how often a patient is rechecked, how aggressively clinicians look for acid-base complications, and how they counsel pet parents about prognosis. It may be especially relevant in dogs that do not yet look dramatically different by creatinine, SDMA, proteinuria, or blood pressure alone. Still, this is early-stage evidence, and the study does not by itself establish that changing therapy based on UACR improves outcomes. (pmc.ncbi.nlm.nih.gov)
There are also practical questions to solve before UACR becomes routine. Reference data exist, but widespread uptake would require assay availability, consistency across laboratories, and clearer guidance on how clinicians should act on a low result. It will also be important to see whether future studies replicate the cutoff, test UACR across broader CKD populations, and evaluate whether interventions aimed at metabolic acidosis or other CKD complications change outcomes in dogs identified as high risk by this marker. (pmc.ncbi.nlm.nih.gov)
What to watch: Expect follow-up work on validation, lab standardization, and whether UACR can move from an interesting prognostic signal to a decision-making tool that fits alongside IRIS-based CKD management. (pmc.ncbi.nlm.nih.gov)