Anion Gap Corrected for Albumin (ACAG)
Info
Na (mEq/L or mmol/L)
Cl (mEq/L or mmol/L)
HCO3 (mEq/L or mmol/L)
Albumin Level (g/dL)
R e s u l t s
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Anion Gap (mEq/L or mmol/L)
 
Adjusted AG (mEq/L or mmol/L)
 
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Anion Gap Corrected for Albumin (ACAG)
  • Corrected anion gap for albumin is used as a diagnosing tool for metabolic acidosis
  • Every 1 gram/dL decrease in albumin will decrease the anion gap by 2.3 mmoles. This can result in patients who actually do have an anion gap; appearing to not have one, due to hypoalbuminemia
  • Helps categorize acidosis.
    • Gap acidosis: salicylates, uremic, methanol, paraldehyde, lactic, ethylene glycol, ketoacidosis
    • Nongapacidosis: carbonic anhydrase inhibitor, Renal tubular acidosis (RTA), ureteral diversions, diarrhea/GI HCO 3 losses

Formula:

Anion gap (AG) = Na - (Cl+HCO 3 )

Each of these items is measured in either mEq/L or mmol/L.

Albumin corrected anion gap (ACAG) = {4 - [observed serum albumin (g/dL] × 2.3} + AG

Where,

AG - anion gap in mEq/L

Observed serum albumin in g/dL

Reference:

  1. Feldman M, Soni N, Dickson B. Influence of hypoalbuminemia or hyperalbuminemia on the serum anion gap. J Lab Clin Med . 2005 Dec;146(6):317-20.