Table 2.

Causes of an elevated serum anion gap

Metabolic acidosis associated with overproduction or decreased excretion of acid
Laboratory error
Severe volume depletion (hyperalbuminemia)
Metabolic alkalosis
Respiratory alkalosisa
Severe hyperphosphatemia
Increased anionic paraproteins
  • a The increase in serum anion gap even with marked reductions in Paco2 is trivial.