Dog BUN Creatinine Ratio Calculator
Calculate BUN:creatinine ratio to differentiate pre-renal, renal, and post-renal azotaemia in dogs.
What Is the Dog BUN Creatinine Ratio Calculator?
Calculate BUN:creatinine ratio to differentiate pre-renal, renal, and post-renal azotaemia in dogs.
The BUN:creatinine ratio differentiates pre-renal azotaemia (dehydration) from intrinsic renal failure. A disproportionately elevated BUN suggests pre-renal cause or GI haemorrhage.
Every result is based on published veterinary research and breed-size-specific growth data — not generic averages. This tool is completely free, works instantly in your browser, and requires no account or sign-up.
How to Use This Calculator
Fill in the required fields above — typically your dog's weight, age, or breed size. Every field has a clear label and hint.
Press the calculate button to get your instant result. No page reload, no account needed, no waiting.
Your result appears immediately below the calculator. It includes the primary answer plus additional context where relevant.
Share, print, or save your result. Always discuss health-related results with your veterinarian before making decisions.
How It Works
The BUN:Creatinine ratio helps differentiate pre-renal, renal, and post-renal causes of azotaemia in dogs. Normally BUN (Blood Urea Nitrogen) and creatinine rise proportionally with reduced GFR. A disproportionately elevated BUN:Creatinine ratio (>20:1 or >40:1 depending on units) suggests pre-renal azotaemia (dehydration, reduced cardiac output, haemorrhage), gastrointestinal bleeding (urea from blood digestion), or high protein diet. A low ratio (<10:1) suggests hepatic disease (reduced urea synthesis), low protein diet, or polyuria/polydipsia causing urea washout.
Normal BUN in dogs: 7–27 mg/dL (2.5–9.6 mmol/L). Normal creatinine: 0.5–1.5 mg/dL (44–133 μmol/L). Normal ratio: 10–20:1 (using mg/dL values).
Sources: Stockham SL, Scott MA. Fundamentals of Veterinary Clinical Pathology 2nd ed 2008; Finco DR, Duncan JR. Evaluation of BUN and serum creatinine in veterinary medicine. JAVMA 1976.
Veterinary Research
Every formula is derived from peer-reviewed veterinary studies and clinical guidelines, not guesswork or generic rules.
Instant Results
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FAQ
Sources & References
This calculator's formulas are based on the following peer-reviewed and authoritative veterinary sources:
- Merck Veterinary Manual u2014 Clinical Reference — Clinical formulas, normal reference ranges, and diagnostic criteria
- WSAVA Guidelines for Veterinary Practice — International veterinary clinical standards
- Ettinger's Textbook of Veterinary Internal Medicine — Advanced clinical reference for fluid therapy, haematology, and diagnostics
- RECOVER Initiative u2014 CPR Guidelines — Emergency drug dosing and resuscitation protocols
⚠️ These calculators are reference tools only. Always consult a licensed veterinarian before administering medication or making medical decisions.