Uric acid in dogs and cats
Uric acid is a breakdown product of purines — building blocks of DNA and RNA from the body’s own cells and from food. In most dogs and cats the liver turns it further into allantoin, which dissolves easily, so little uric acid builds up. Open veterinary sources say little about the blood value in dogs and cats; most of what is known concerns Dalmatians and urate stones.
What it shows
In almost all mammals the liver has an enzyme, urate oxidase (uricase), that converts uric acid into allantoin, and allantoin leaves in the urine. People and other primates lost this enzyme during evolution — so uric acid plays a different role in human medicine, and human reference figures do not fit dogs and cats.
Dalmatians are the exception among dogs. Their livers do have working urate oxidase, but uric acid is carried poorly into liver cells, and the kidneys hardly take it back from the urine. As a result, Dalmatians pass large amounts of uric acid in the urine (hyperuricosuria) and have relatively higher blood uric acid than other dogs. The cause is a change in the SLC2A9 gene, which encodes a uric acid transporter.
In birds, by contrast, uric acid is the main end product of nitrogen metabolism and is used as a kidney marker — another reason not to borrow interpretations across species.
Higher than reference — what it may be a sign of
- Dalmatian metabolism. A relatively high value compared with other dogs is a feature of the breed, not a disease by itself. The practical risk lies in the urine: poorly soluble urate can form crystals and stones.
- The same gene change in other breeds. It has been found in some English Bulldogs and Black Russian Terriers, and hyperuricosuria can occur in any breed.
- Liver shunt (portosystemic shunt). Blood bypasses the liver, uric acid is broken down less, and ammonium urate crystals and stones can form. These sources describe the change in urine; how far blood uric acid rises in such animals is not described there.
A raised value is a sign, not a diagnosis. A vet looks at the urine, the breed and liver tests before drawing any conclusion.
Lower than reference
The open sources used here describe no particular meaning of a low blood uric acid in dogs or cats. A low value on its own is not a known problem; a vet reads it next to the rest of the panel. Note that “low uric acid” Dalmatians, bred from a Dalmatian × Pointer cross to carry the normal gene, are defined by their urine, not by a blood value.
Look at together with
- Urate crystals in urine and urine crystals overall — where uric acid problems actually show up.
- Bile acids and ammonia — to look for a liver shunt. Ammonium urate crystals together with high bile acids almost certainly point to excess ammonia in the blood, which is typical of a portosystemic shunt; dogs with the inherited transport defect have neither abnormality.
- A DNA test for hyperuricosuria — helps separate urate stones caused by the gene change from those caused by other conditions.
Units and conversion
Uric acid is reported in µmol/L or mg/dL. One mg/dL equals 59.48 µmol/L, so 2 mg/dL is about 119 µmol/L. In the app each row keeps the unit printed on the form; the chart converts to µmol/L so forms from different labs line up.
Reference range
The reference range is on your lab’s form. Use only a range made for dogs or cats: human ranges come from a species without urate oxidase and do not apply. In a Dalmatian a value that is higher than in other dogs is expected for the breed. For uric acid the urine usually tells more than the blood, so the vet reads the number next to the urinalysis.
Cats and dogs
Urate crystals occasionally appear in cats with inborn errors of uric acid transport. In cats with a congenital liver shunt, ammonium urate crystals in urine have been reported in up to 42% across studies. No cat breed with a Dalmatian-like defect is described in these sources.
All Dalmatians tested carry two copies of the gene change, so they pass a lot of uric acid in the urine. In a dog of a breed not known for hyperuricosuria, urate stones prompt a check for a liver shunt, including bile acids. Ammonium urate crystals in urine have been reported in up to 57% of dogs with a congenital shunt across studies.
Add a lab form — Pet Tracker Space recognises the lines, keeps the form’s units and draws each indicator over time with your lab’s reference band.
Sources
- Bannasch D, Safra N, Young A, et al. Mutations in the SLC2A9 Gene Cause Hyperuricosuria and Hyperuricemia in the Dog. PLoS Genetics 2008;4(11):e1000246.
- Van Vertloo L. Urolithiasis in Dogs. Merck Veterinary Manual, professional version, full review May 2025.
- UC Davis School of Veterinary Medicine. Health topics — Hyperuricosuria (canine).
- Center SA. Miscellaneous Serum Biochemical Measures in Hepatic Disease in Small Animals. Merck Veterinary Manual, professional version, full review August 2023.
- Konstantinidis AO, Patsikas MN, Papazoglou LG, Adamama-Moraitou KK. Congenital Portosystemic Shunts in Dogs and Cats: Classification, Pathophysiology, Clinical Presentation and Diagnosis. Veterinary Sciences 2023;10(2):160.
- eClinPath (Cornell University College of Veterinary Medicine). Uric acid — exotics / chemistry.
This page explains what a lab value means. It is not a diagnosis and not a substitute for your veterinarian — only they can interpret results for your pet.