Acid–Base Tool
Anion Gap Calculator
Calculate the anion gap, albumin-corrected anion gap, and delta gap to evaluate metabolic acidosis and screen for mixed acid–base disorders. For deeper learning, review our anion gap guide and delta gap guide.
How to use the anion gap and delta gap
- Step 1Enter sodium, chloride, and bicarbonate to calculate the raw anion gap.
- Step 2Add albumin to generate a corrected anion gap, which is especially useful when albumin is low.
- Step 3If the corrected gap is elevated and bicarbonate is low, review the delta ratio to screen for mixed metabolic disorders. You can also read the delta gap guide.
- Step 4Use the interpretation blocks below with the ABG Analyzer and Winter’s Formula to complete the acid–base picture.
Clinical pearls
When the anion gap is elevated
Think about lactate, ketoacids, renal failure, or toxins. The corrected gap is especially helpful when albumin is low. For a fuller breakdown, read the anion gap guide.
When the delta ratio matters
A low delta ratio suggests a concurrent normal anion gap metabolic acidosis, while a high ratio can suggest metabolic alkalosis or chronic respiratory acidosis on top of the high-gap process. Review the delta gap article.
Supporting acid–base tools
Use these tools together to build a fuller metabolic acidosis and mixed-disorder workup.