定義 編輯

Determination of the plasma anion gap (AG) is an important step in approaching the differential diagnosis of metabolic acidosis

The "real" balance is given by the equation:

[Na] + [other cations] = [Cl] + [HCO3] + [other anions]


[Na] - ([Cl] + [HCO3]) = [other anions] - [other cations] = "Anion Gap"

正常範圍 編輯

  • 12-16 mEq/L

Elevated anion gap 編輯

  1. Lactic acidosis, usually due to marked systemic hypoperfusion or to malignancy.
  2. Ketoacidosis due to diabetes mellitus, alcohol, or fasting, in which ??-hydroxybutyrate is the primary unmeasured anion.
  3. Most patients with renal failure
  4. Ingestions, in which the major retained anions are formate with methanol, glycolate and oxalate with ethylene glycol, and ketones and lactate with aspirin.

High Anion Gap Metabolic Acidosis 鑑別診斷編輯


  • alcohol
  • methanol/metformin
  • uremia
  • diabetic ketoacidosis
  • paraldehyde/phenformin
  • iron/isoniazid
  • lactic acidosis
  • ethylene glycol
  • salicylates

Normal Anion Gap Metabolic Acidosis 鑑別診斷=編輯