🧪 Anion Gap Calculator
Calculate the serum anion gap, with optional albumin correction, to work up a metabolic acidosis.
Anion Gap Calculator
Sodium (Na⁺) (mmol/L)
Chloride (Cl⁻) (mmol/L)
Bicarbonate (HCO₃⁻) (mmol/L)
Albumin (optional) (g/dL)
When to use
Evaluate acid–base disorders; distinguish high- from normal-anion-gap acidosis.
How it works
AG = Na − (Cl + HCO₃); reference ~8–12 mmol/L. Corrected AG = AG + 2.5 × (4 − albumin g/dL).
Key points
- A high gap points to lactate, ketones, toxins or uraemia.
- Low albumin lowers the measured gap — always correct it.
- Reference range is laboratory-dependent.
References
Decision support for licensed clinicians only; not a substitute for clinical judgement, diagnosis or local protocols.