Acid-Base

Delta Ratio Calculator

Compares the rise in anion gap with the fall in bicarbonate to uncover a second acid-base disorder behind a gap acidosis.

Reviewed by Alex G, BSN, RN, CEN, CCRN, CMC, NREMT-P · From the Reference tab of the app

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Formula

(AG - 12) / (24 - HCO3)

How it is used

• Used to determine if a mixed acid-base disorder is present in the setting of an elevated Anion Gap Metabolic Acidosis (AGMA).

• < 0.4: Hyperchloremic normal anion gap acidosis.
• 0.4 to 0.8: Mixed high AG and normal AG acidosis.
• 1 to 2: Pure High AG Metabolic Acidosis.
• > 2: Mixed High AG acidosis and concurrent Metabolic Alkalosis (or chronic respiratory acidosis).

Same formula as the app. Open it in the web app.

Related one-pagers

• ABG Interpretation in 6 StepsDelta ratio = (corrected gap − 12) ÷ (24 − HCO₃⁻), a rough guide

Related calculators

• Albumin-corrected Anion Gap
• Osmolar Gap
• Serum Osmolality
• Winters' Formula

For education and exam preparation only. Follow your institution’s protocols. For education and exam preparation only. Verify results independently and follow your institution’s protocols. Not a substitute for clinical judgment.