Delta Gap / Delta Ratio (Acid-Base)
Delta gap / delta ratio (acid-base): (anion gap − normal AG) − (normal HCO₃ − measured HCO₃) and the ratio of AG excess to bicarbonate deficit, disclosing a concurrent non-anion-gap or metabolic-alkalosis component.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Sodium
- 140 mEq/L
- Chloride
- 100 mEq/L
- Bicarbonate
- 10 mEq/L
Result: Delta ratio 1.29 — a pure high-anion-gap metabolic acidosis (1–2).
The tool opens with these values already filled in. Replace them with your own.
What the result means
- Bands
- < 0.4 a concurrent non-anion-gap acidosis; 0.4 to < 0.8 mixed; 0.8 to < 1 borderline; 1–2 a pure high-anion-gap acidosis; > 2 a coexisting metabolic alkalosis or chronic respiratory acidosis.
What you enter
- Sodium
- Chloride
- Bicarbonate
- Albumin (optional, for corrected AG)
- Normal anion gap (default 12)
- Normal bicarbonate (default 24)
How this is calculated
- Formula
- Delta ratio = (anion gap − normal AG) / (normal HCO₃ − measured HCO₃), with an optional albumin correction of the anion gap.
Wrenn K. The delta (delta) gap: an approach to mixed acid-base disorders. Ann Emerg Med. 1990;19(11):1310-1313. Corroborated by Rastegar A. Use of the delta AG / delta HCO3 ratio in the diagnosis of mixed acid-base disorders. J Am Soc Nephrol. 2007;18(9):2429-2431. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.