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Albumin-Corrected Delta Ratio

Albumin-corrected delta ratio = (albumin-corrected AG − 12) ÷ (24 − HCO₃), with corrected AG = Na − (Cl + HCO₃) + 2.5 × (4 − albumin g/dL). <0.4 normal-gap acidosis, 0.4–0.8 mixed high- and normal-gap acidosis, 0.8–2 pure high-gap acidosis, >2 concurrent metabolic alkalosis or chronic respiratory acidosis.

Serum sodium (mmol/L or mEq/L)
Serum chloride (mmol/L or mEq/L)
Serum bicarbonate (HCO₃⁻) (mmol/L or mEq/L)
Serum albumin (g/dL or g/L)

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Interpretation

Result	Meaning
< 0.4	Normal-gap acidosis
0.4–0.8	Mixed high-gap + normal-gap acidosis
0.8–2.0	Pure high-gap acidosis (DKA ≈ 1, lactic ≈ 1.6)
> 2.0	Plus metabolic alkalosis or chronic respiratory acidosis

Formula

Delta ratio = [Na⁺ − (Cl⁻ + HCO₃⁻) + 2.5 × (4 − albumin g/dL) − 12] ÷ (24 − HCO₃⁻)

Clinical pearls

Unreliable when the bicarbonate fall is small (mild acidosis); interpret with pH and pCO₂.
Matches the MedCalc-Bench definition. Deliberate difference: when HCO₃ ≥ 24 this tool reports "not applicable" rather than dividing by zero or a negative number.

Examples

albumin corrected delta ratio na 140 cl 100 hco3 14 alb 2 corrected delta ratio sodium 137 chloride 104 bicarbonate 18 albumin 4 g/dL

FAQ

What does a corrected delta ratio of 1–2 mean?

The anion gap rose about as much as (or a bit more than) bicarbonate fell, consistent with a pure high-anion-gap metabolic acidosis such as DKA or lactic acidosis.

Should I use the albumin-corrected or uncorrected delta ratio?

Use the corrected version when albumin is low; otherwise a high-gap acidosis can be missed or misclassified as normal-gap.

Evidence

Nephrology & Electrolytes · Reviewed 2026-10-14 · Methodology