Use of the anion gap in clinical medicine

James R. Oster, Guido O. Perez, Barry J. Materson

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


The anion gap (AG) in the serum equals the concentrations of Na - (Cl + HCO3). It is becoming increasingly useful in the interpretation of acid-base disorders and in the diagnosis of other conditions. In an acidemic patient, an elevated AG usually indicates the presence of an organic acidosis, rhabdomyolysis, nonketotic hyperglycemic coma, uremia, or certain intoxications. An increased AG with alkalemia suggests severe alkalosis with hemoconcentration or use of anionic antibiotics (eg, carbenicillin) or salts of organic acids (eg, citrate). An elevated AG with a normal serum pH could be an artifact caused by prolonged exposure of the serum sample to air before processing. A decreased AG with a normal serum pH may indicate hypoalbuminemia, cationic paraproteinemia, halide poisoning, or lithium intoxication. The ΔAG/ΔHCO3 ratio and the urinary AG may also be quite useful in analyzing complex acid-base disorders.

Original languageEnglish (US)
Pages (from-to)229-237
Number of pages9
JournalSouthern medical journal
Issue number2
StatePublished - Feb 1988

ASJC Scopus subject areas

  • Medicine(all)


Dive into the research topics of 'Use of the anion gap in clinical medicine'. Together they form a unique fingerprint.

Cite this