FrançaisWhat creatinine measures
Creatinine is a waste product of muscle. The kidneys filter it freely and do not reabsorb it, which makes it a more reliable marker of filtration than BUN, because diet barely affects it [1]. The Merck Veterinary Manual lists 0.5–1.7 mg/dL (44–150 µmol/L) for dogs [2]; your laboratory has its own interval.
It is an insensitive marker: creatinine rises only after about a third of the filtering capacity and three quarters of the kidney mass are lost [1]. That is why vets often read it with SDMA, which tends to rise earlier.
How to read the creatinine line
Here is an example line, followed by a converter for reports in other units.
- Abbreviation CREA, CREAT or creatinine.
- Result 2.1 mg/dL in this illustrative line: above the interval.
- Unit mg/dL in the United States, µmol/L in Europe: 2.1 mg/dL ≈ 186 µmol/L (× 88.4) [1].
- Laboratory interval The example uses the dog interval of the Merck Veterinary Manual [2].
- Flag H: above the interval. Your vet checks hydration, the urine concentration and the trend before concluding [1, 3].
Unit converter
Equivalent values
- Creatinine, µmol/L–
- Creatinine, mg/L–
Conversion only changes the unit. Compare the result with the interval printed by the laboratory that measured it.
What changes creatinine besides the kidneys
- Muscle mass. Muscular dogs run higher; small dogs, young dogs and dogs losing muscle run lower, which can hide a kidney problem [1].
- Greyhounds and sighthounds. Healthy Greyhounds have higher creatinine; one published upper limit is 2.0 mg/dL [1]. IRIS notes that this can place healthy individuals outside the laboratory interval [3], and Greyhounds also have higher urine creatinine [4].
- Dehydration. Less blood reaches the kidneys, so creatinine and BUN rise together; the urine concentration helps tell this apart from kidney disease [1].
- Meals. A usual meal caused no consistent rise over 8 hours in 100 healthy dogs; a cooked meat meal can raise it mildly [1].
The IRIS stages for dogs
| IRIS stage | Creatinine (mg/dL) | Creatinine (µmol/L) | SDMA (µg/dL) |
|---|---|---|---|
| 1 | below 1.4 | below 125 | below 18 |
| 2 | 1.4–2.8 | 125–250 | 18–35 |
| 3 | 2.9–5.0 | 251–440 | 36–54 |
| 4 | above 5.0 | above 440 | above 54 |
Staging is not a diagnosis on its own: it follows a diagnosis of chronic kidney disease and is completed by the urine protein:creatinine ratio and blood pressure [3]. For sudden kidney injury, IRIS considers a rise of more than 0.2 mg/dL within 48 hours significant [1].
Why the trend matters more than one value
Creatinine varies little within the same dog, so comparing a dog with its own previous results is more sensitive than comparing it with a population interval. A value that climbs from 0.8 to 1.3 mg/dL can matter even though both are “normal” [1].
Results often read with creatinine
For cats, see creatinine and BUN in cats.
En français : créatinine du chien.
Questions to ask your veterinarian
- Is the creatinine high once hydration and muscle mass are considered?
- What do the urine concentration and SDMA show?
- How does this compare with my dog’s previous results?
- Should the test be repeated on a fasting sample before staging?
- Should we check urine protein and blood pressure?
Get your dog’s kidney values explained together.
AI DiagAnimals reads creatinine with BUN, SDMA, the urinalysis and your laboratory’s intervals, and prepares the questions for your vet. The service opens soon: leave your email to be told first.
Frequently asked questions
What is a normal creatinine level for a dog?
Roughly 0.5–1.7 mg/dL (44–150 µmol/L) in the Merck Veterinary Manual table; your laboratory’s interval applies [2].
When should I worry about creatinine levels in my dog?
When a high value persists on a repeat fasting sample with dilute urine, or when it climbs from one test to the next. A single mildly high value in a dehydrated or muscular dog is often re-checked first [1, 3].
What causes high creatinine in dogs?
Reduced kidney filtration, from dehydration, kidney disease or a urinary blockage. High muscle mass and breed (Greyhounds) can also give higher values without disease [1].
Can a dog recover from high creatinine?
If the cause is dehydration or a sudden, treatable kidney injury, creatinine can return to normal. Chronic kidney disease does not reverse, but it can often be slowed and managed for a long time.
What should I feed a dog with high creatinine?
Ask your vet before changing the diet: kidney diets are chosen according to the stage, urine protein and phosphorus, not creatinine alone.
Sources
- eClinPath, Cornell University College of Veterinary Medicine. Creatinine. eclinpath.com/chemistry/kidney/creatinine
- Merck Veterinary Manual. Serum biochemical analysis reference ranges. merckvetmanual.com/reference-values-and-conversion-tables/reference-guides/serum-biochemical-analysis-reference-ranges
- International Renal Interest Society (IRIS). IRIS Staging of CKD, modified 2026. iris-kidney.com/s/IRIS_staging_guidelines-2026.pdf
- Liffman R et al. Urine creatinine concentration and urine protein-to-creatinine ratios in healthy nonracing Greyhounds. Vet Clin Pathol. 2020;49(2):270-278. doi.org/10.1111/vcp.12856
Laboratory methods and reference intervals vary. This article explains; it does not diagnose. For a decision about your pet, use the original report and talk to your veterinarian. Our editorial policy.