Anion Gap Calculator
Serum anion gap with optional albumin correction and MUDPILES differential prompts.
Understanding this tool
Why nurses use it
The serum anion gap helps nurses and clinicians interpret metabolic acidosis — distinguishing high-gap states (DKA, lactic acidosis, toxins) from normal-gap acidosis. Albumin correction improves accuracy when albumin is low.
When to use it
Use when reviewing blood gas or electrolyte results in suspected acidosis, DKA, sepsis, or toxic ingestion workups.
Calculate
How to use this calculator
- Enter sodium, chloride, and bicarbonate from the same blood sample.
- Optionally enter albumin for corrected anion gap.
- Interpret with pH, lactate, ketones, and clinical context.
How the calculation works
AG = Na − (Cl + HCO₃). Corrected AG adds 2.5 × (4 − albumin) when albumin is below 4 g/dL. Elevated gap suggests unmeasured anions.
Formula used by this tool — verify units before applying at the bedside.
Worked example
Limitations & clinical notes
- Reference range ~3–11 mEq/L varies by lab.
- Albumin correction recommended when albumin is low.
References
Key sources: Core clinical acid-base physiology.
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Disclaimer: This calculator is for educational and bedside double-check purposes only. It does not replace institutional protocols, prescriber orders, pharmacist verification, or clinical judgment. Always follow your local policies — especially for high-risk medications, infusions, pediatrics, and critical care. If the patient is acutely unwell, escalate immediately rather than relying on any calculator output.