Anion Gap and Delta-Delta Calculator
Calculates anion gap and delta-delta (delta gap) to identify mixed metabolic acid-base disorders. The anion gap identifies high anion gap metabolic acidosis; the delta gap detects concurrent metabolic alkalosis or non-anion gap acidosis.
mEq/L (mmol/L)
Measured serum sodium concentration. Must be same units as chloride and bicarbonate.
mEq/L (mmol/L)
Measured serum chloride concentration.
mEq/L (mmol/L)
Measured serum bicarbonate (or total CO2).
g/dL
If hypoalbuminemia present, corrected anion gap = calculated AG + 2.5 * (4 - albumin).
References
- Acid-Base Disorders - Merck Manual Professional Edition — Merck Manuals (2025)
- The delta anion gap/delta HCO3 ratio in patients with a high anion gap metabolic acidosis — UpToDate (2024)
- Modified Delta Gap Equation for Quick Evaluation of Mixed Metabolic Acid-Base Disorders — Cureus/PMC (2012)
Note: The delta gap equation can be simplified to Na - Cl - 36 when bicarbonate is unavailable. For ABG interpretation, always confirm with Winters formula for respiratory compensation.
Warnings & Limitations
- Does not replace arterial blood gas interpretation.
- Albumin correction recommended in hypoalbuminemia (common in ICU/liver disease).
- Delta gap assumes normal AG = 12; some labs use 10. Adjust if needed.
- Must be interpreted alongside pH, PaCO2 (Winters formula), and clinical context.