Clinical Tools / Acid-base & electrolytes
Blood gas analyzer
Interpret acid-base disorders, calculate anion gap with albumin correction, assess compensation, and estimate osmolality from blood gas and electrolyte values.
Acid-base interpretation support for veterinary blood gas review.
Use it for
Interpreting blood gas results and identifying primary acid-base disorders in dogs and cats.
It calculates
Primary disorder, compensation status, anion gap, delta ratio, osmolality, and osmolar gap.
It does not decide
Treatment plans, fluid therapy, or bicarbonate supplementation. Clinical correlation required.
Input
Enter blood gas values
Required: pH, pCO₂, HCO₃⁻, Na⁺, Cl⁻. Optional fields improve interpretation accuracy.
Safety checks
Review before acting on results
- Reference ranges: Dog pH 7.35–7.45, Cat pH 7.31–7.41. pCO₂ dog 35–45, cat 29–42 mmHg. HCO₃⁻ dog 22–26, cat 17–23 mEq/L.
- Albumin correction: Anion gap is adjusted for hypoalbuminemia using the formula: AG + (2.5 × [3.5 − albumin]).
- Delta ratio: Values <1 suggest concurrent non-anion gap metabolic acidosis; >2 suggests concurrent metabolic alkalosis.
- What still needs checking: Patient hydration status, lactate, electrolyte trends, and clinical picture before fluid or bicarbonate therapy.
Basis
Clinical basis & references
How the interpretation logic works and what references it draws from.
Basis
Clinical basis & references
How the interpretation logic works and what references it draws from.
- Primary disorder: pH < 7.35 = acidemia; > 7.45 = alkalemia. Low HCO₃⁻ with low pH = metabolic acidosis. High pCO₂ with low pH = respiratory acidosis. High HCO₃⁻ with high pH = metabolic alkalosis. Low pCO₂ with high pH = respiratory alkalosis.
- Compensation (Winter's formula): Expected pCO₂ = (1.5 × HCO₃⁻) + 8 ± 2. For metabolic alkalosis: expected pCO₂ = (0.7 × HCO₃⁻) + 20 ± 1.5.
- Respiratory compensation: Acute: HCO₃⁻ changes ~0.15 mEq/L per 1 mmHg pCO₂ change. Chronic: ~0.35 mEq/L per 1 mmHg.
- Anion gap: Na − (Cl + HCO₃). Normal dog ~12–24, cat ~13–27. Albumin-corrected AG adds 2.5 mEq/L per 1 g/dL albumin below 3.5.
- Osmolality: 2(Na) + glucose/18 + BUN/2.8. Normal ~290–310 mOsm/kg. Osmolar gap > 15 suggests unmeasured osmoles (toxins, mannitol).
Math & Method
Calculation audit trail
Step-by-step math used for the current interpretation.
Math & Method
Calculation audit trail
Step-by-step math used for the current interpretation.
Enter values and select Interpret to show the calculation method.
Learn
Quick clinical guide
High-yield patterns for common acid-base presentations.
Learn
Quick clinical guide
High-yield patterns for common acid-base presentations.
- Metabolic acidosis + high AG: Think lactic acidosis, uremia, ketoacidosis, or toxins (ethylene glycol, salicylates).
- Metabolic acidosis + normal AG: Think GI bicarbonate loss (diarrhea), renal tubular acidosis, or dilutional acidosis.
- Respiratory acidosis: Think airway obstruction, pulmonary disease, neuromuscular weakness, or CNS depression.
- Metabolic alkalosis: Think vomiting of gastric contents, diuretic use, or primary hyperaldosteronism.
- Respiratory alkalosis: Think hypoxemia, pain, anxiety, fever, or CNS stimulation.
- High osmolar gap: Think ethylene glycol, methanol, ethanol intoxication, or mannitol administration.