Notes & Sources

• Potassium is excluded, which is the convention in most laboratories. If your institution includes K⁺, the normal range shifts upward by roughly 4 mEq/L.
• Albumin correction matters. Albumin is the dominant unmeasured anion; each 1 g/dL fall lowers the measured gap by about 2.5 mEq/L. A hypoalbuminaemic patient can have a normal-looking gap while a genuine high-anion-gap acidosis is present.
• The delta ratio is shown only when the corrected gap exceeds 12, and is used to detect a second, coexisting acid–base disorder.
• Reference range used here: 8–12 mEq/L. Adjust to your own laboratory’s range.