Arithmetic support
Anion gap calculator
Calculate the transparent anion-gap arithmetic result from sodium, chloride, and bicarbonate. This tool does not apply a reference interval, diagnose an acid-base disorder, or direct treatment.
Safety checks
- Arithmetic only; no reference interval, diagnosis, or treatment direction is applied.
- Confirm laboratory units and specimen context before using the arithmetic result.
- This calculator does not retain patient records or results.
Basis and limits
- Calculation: AG = Na⁺ − (Cl⁻ + HCO₃⁻).
- Compare tools: this formula omits K⁺. The Blood Gas Analyzer uses Na⁺ + K⁺ − (Cl⁻ + HCO₃⁻), so its result will differ by the measured K⁺ value for the same sample. Compare each result with a reference interval calculated using the same formula.
- Units: enter sodium, chloride, and bicarbonate in the same mEq/L laboratory unit path.
- Scope: this tool provides arithmetic only. It does not apply albumin correction, delta-ratio thresholds, a reference interval, a diagnostic classification, or a treatment recommendation.
Formula audit trail
Last reviewed: May 2026
Scope: arithmetic support only. Verify laboratory units and any diagnostic interpretation against current references and clinical judgment.