Calculate the serum anion gap, the albumin-corrected gap and the delta ratio to classify metabolic acidosis and spot mixed acid–base disorders.
About this tool
Anion gap, albumin-corrected gap and delta ratio.
How to use Anion Gap Calculator
- Enter sodium, chloride and bicarbonate (and potassium if your lab includes it).
- Add albumin to correct the gap for hypoalbuminemia.
- Read the gap, the delta ratio and the interpretation.
Worked example
Na 140, Cl 100 and HCO₃ 14 give an anion gap of 26 mmol/L, a high anion gap metabolic acidosis with a delta ratio of 1.4.
What is a normal anion gap?
Usually about 8–16 mmol/L without potassium, but it varies by analyzer, so use your laboratory’s range.
Why correct for albumin?
Albumin is the main unmeasured anion. Each 1 g/dL fall lowers the gap by about 2.5, which can hide a high-gap acidosis.
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