What is the anion gap used for in veterinary medicine?

The anion gap helps classify metabolic acidosis. A high gap suggests unmeasured anions such as lactate, ketones, or uremic toxins. A normal gap suggests bicarbonate loss through the GI tract or kidneys.

Why should albumin be considered when interpreting anion gap?

Albumin is a major unmeasured anion. Low albumin lowers the anion gap, which can mask a true high-gap acidosis. Correcting for albumin improves diagnostic accuracy.

What does the delta ratio tell you?

The delta ratio compares the change in anion gap to the change in bicarbonate. It helps distinguish pure high-gap acidosis from mixed disorders, such as concurrent non-anion gap acidosis or metabolic alkalosis.

Clinical decision support

Anion gap calculator

Calculate anion gap with albumin correction for dogs and cats.

Species

Sodium (mmol/L) Chloride (mmol/L)

HCO₃⁻ (mmol/L) Albumin (g/dL, optional)

Educational support only. Verify with clinical judgment.

Reference ranges & correction factor

Dog AG ref min Dog AG ref max Cat AG ref min Cat AG ref max

Dog albumin ref (g/dL) Cat albumin ref (g/dL)

Correction factor Dog normal HCO₃⁻

Cat normal HCO₃⁻

Defaults are commonly cited references. Adjust to match your laboratory.

Anion gap

— mEq/L

Enter electrolytes

Enter sodium, chloride, and HCO₃⁻ to calculate.

Corrected AG —

Enter albumin to enable.

Delta ratio —

—

Interpretation —

—

Clinical next steps

Correlate with lactate, ketones, toxin exposure, and renal function.
Review blood gas for pH, pCO₂, and compensation.
Consider albumin context and whether correction changes the picture.
If delta ratio suggests mixed disorder, evaluate for concurrent GI losses.

Safety checks

This tool supports calculation and education only.
It does not diagnose or replace current references.
Verify with hospital protocols and veterinarian judgment.
Confirm units are mmol/L for electrolytes and g/dL for albumin.

Basis and limits

Calculation: AG = Na⁺ − (Cl⁻ + HCO₃⁻).
Albumin correction: AG + factor × (ref albumin − measured) when low.
Delta ratio: ΔAG / ΔHCO₃⁻.
Scope: Supports arithmetic and pattern recognition only.

Formula audit trail

Anion gap calculator

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