Chemistry

Anion Gap

Serum anion gap for metabolic acidosis.

Education and reference only. Not a substitute for clinical judgement, local policy or product labelling. Always verify before clinical use. Values are calculated in your browser and never stored.

When to use

Use when investigating a metabolic acidosis to distinguish high-anion-gap from normal-anion-gap causes.

Why use

It rapidly narrows the differential in acidosis.

Critical actions

Reference range is lab-dependent (≈8–12). Correct for albumin in hypoalbuminaemia (a low albumin lowers the apparent gap).

Evidence & references

Anion gap = Na⁺ − (Cl⁻ + HCO₃⁻).

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