Open AccessClinical utility of anion gap in deciphering acid–base disorders
Author(s) -
Reddy P.,
Mooradian A. D.
Publication year - 2009
Publication title -
international journal of clinical practice
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.756
H-Index - 98
eISSN - 1742-1241
pISSN - 1368-5031
DOI - 10.1111/j.1742-1241.2009.02000.x
Subject(s) - anion gap , medicine , metabolic acidosis , alkalosis , acidosis , metabolic alkalosis , bicarbonate , delta , urine , excretion , acid–base reaction , endocrinology , gastroenterology , chemistry , organic chemistry , engineering , aerospace engineering
Summary The anion gap (AG) measurement is a very useful tool in the evaluation of patients with acid–base disorders. Once metabolic acidosis is identified, AG will provide the important first step in the differential diagnosis of disorders that either increase the AG and those that leave the AG unchanged. Delta gap is the comparison between change (delta) in the AG and the change (delta) in bicarbonate (HCO 3 − ). Delta ratio, defined as delta AG:delta HCO 3 − is usually 1 : 1 in patients with an uncomplicated high AG acidosis. A value below 1 : 1 suggests a combined high and normal AG acidosis. A value above 2 : 1 suggests a combined metabolic alkalosis and a high AG acidosis. Urine AG (unmeasured anions–unmeasured cations) is an indirect estimate of the urine NH 4 + excretion. It is typically negative in patients with normal AG metabolic acidosis secondary to diarrhoea. Utilisation of AG calculations helps clinicians in identifying and treating acid–base disorders.