Urine ammonia ratio may help predict canine CKD outcomes
Bottom line
Dogs with chronic kidney disease may have a new, noninvasive way to identify higher-risk patients earlier. A prospective study published January 21, 2026, in the Journal of Veterinary Internal Medicine found that dogs with CKD had significantly lower urine ammonia-to-creatinine ratios, or UACR, than healthy dogs, and that lower UACR tracked with worse renal function. In related coverage published May 29, 2026, dvm360 reported that dogs with UACR below 2.0 had faster disease progression and shorter survival, positioning the marker as a possible prognostic tool alongside existing CKD staging and monitoring approaches. The work comes from investigators at North Carolina State University and the University of Florida, and builds on earlier research that established a reference interval for UACR in healthy dogs. (pubmed.ncbi.nlm.nih.gov)
Why it matters: For veterinary teams, the appeal is practical: UACR is urine-based, noninvasive, and tied to a biologically relevant process, impaired ammonia excretion, that may reflect acid-base dysregulation before metabolic acidosis is obvious on routine testing. CKD in dogs is typically staged using creatinine and SDMA, with additional attention to proteinuria and blood pressure under IRIS guidance, but those tools don't directly capture renal acid excretion. If follow-up studies validate prognostic cutoffs and show that treatment decisions based on UACR improve outcomes, the test could help identify which dogs need closer monitoring, earlier diet changes, or more aggressive management of complications. (pubmed.ncbi.nlm.nih.gov)
What to watch: The next step is whether larger longitudinal studies confirm the proposed UACR threshold and whether IRIS or specialty clinicians begin incorporating ammonia excretion into routine CKD risk stratification. (dvm360.com)
Key facts
- Study type
- Prospective study
- Publication date
- January 21, 2026
- Journal
- Journal of Veterinary Internal Medicine
- Sample size
- 46 healthy dogs, 50 dogs with stable CKD
- Main finding
- Dogs with CKD had lower urine ammonia-to-creatinine ratios than healthy dogs
- Association
- Lower UACR tracked with worse renal function and higher serum creatinine
- Reported cutoff
- UACR below 2.0
- Clinical implication
- Dogs with UACR below 2.0 had faster progression and shorter survival, per dvm360 coverage
- Institutions
- North Carolina State University and the University of Florida
A urine biomarker that reflects renal acid handling may be moving closer to clinical relevance in canine CKD. In a prospective study published January 21, 2026, in the Journal of Veterinary Internal Medicine, researchers found that dogs with chronic kidney disease had markedly lower urine ammonia-to-creatinine ratios than healthy dogs, and that UACR was inversely correlated with serum creatinine. Subsequent reporting from dvm360 on May 29, 2026, added a more clinically pointed takeaway: dogs with UACR below 2.0 experienced faster progression and shorter survival, suggesting the marker may help flag higher-risk patients earlier in the disease course. (pubmed.ncbi.nlm.nih.gov)
The idea has been building for several years. In human nephrology, impaired ammonia excretion is linked to metabolic acidosis and worse CKD outcomes, and veterinary researchers have been asking whether the same physiology could help explain progression in dogs. A prior study established a reference interval for UACR in healthy adult dogs and suggested the test might eventually offer prognostic value. The new canine CKD work extends that foundation by comparing healthy dogs with stable IRIS stage 2 to 4 CKD patients and examining how UACR moves with markers of renal dysfunction. (pmc.ncbi.nlm.nih.gov)
In the January 2026 study, the investigators enrolled 46 healthy dogs and 50 dogs with stable CKD. Median UACR was 7.1 in healthy dogs, compared with 2.2 in dogs with CKD, and the association between lower UACR and higher serum creatinine remained even after controlling for age, body weight, electrolytes, urine specific gravity, and other renal variables. Notably, the PubMed abstract indicates there was no significant difference in UACR between early-stage and late-stage CKD groups, which may support the idea that impaired ammonia excretion appears relatively early rather than only in advanced disease. (pubmed.ncbi.nlm.nih.gov)
That early signal is what makes the biomarker interesting clinically. IRIS guidance remains centered on creatinine and SDMA for staging stable CKD, with proteinuria and systemic blood pressure used to further characterize risk and guide treatment. Standard renoprotective management also includes renal diets, phosphorus control, and management of proteinuria and hypertension. UACR would not replace those tools, but it may add a different layer of information by capturing renal acid-base handling, an area current frontline markers don't directly measure. (iris-kidney.com)
The study also fits with a broader concern around metabolic acidosis in canine kidney disease. Prior veterinary literature has documented serum bicarbonate deficiency in dogs with acute and chronic kidney disease, and the new ammonia work is consistent with the hypothesis that reduced renal ammonia excretion contributes to acid-base imbalance as kidney function declines. dvm360 framed the clinical implication more directly, reporting that dogs with UACR below 2.0 had faster progression and shorter survival, which, if validated, would give clinicians a concrete threshold to discuss with pet parents and use in follow-up planning. (pmc.ncbi.nlm.nih.gov)
No major outside expert commentary was readily available in indexed coverage, but the institutional and specialty context matters. The study authors are affiliated with North Carolina State University and the University of Florida, and the work was supported by the American Kennel Club Canine Health Foundation, according to the PubMed record. That doesn't settle the question of clinical adoption, but it does suggest this is being developed within mainstream academic nephrology rather than as a niche commercial claim. (pubmed.ncbi.nlm.nih.gov)
Why it matters: For veterinary professionals, the most useful takeaway is not that UACR is ready to become a standalone standard of care, but that it may help close a meaningful gap in CKD monitoring. Dogs can look stable by conventional staging while still carrying unmeasured physiologic risk. A urine-based marker tied to acid excretion could eventually help identify which patients need tighter recheck intervals, earlier nutritional intervention, or closer monitoring for acid-base complications, especially if future studies confirm that low UACR predicts outcomes independently of creatinine, SDMA, proteinuria, and blood pressure. (pubmed.ncbi.nlm.nih.gov)
What to watch: The key questions now are whether the sub-2.0 cutoff holds up in larger cohorts, whether serial UACR measurement outperforms one-time sampling, and whether intervention studies show that acting on a low UACR changes progression or survival enough to influence IRIS-aligned practice guidelines. (dvm360.com)