Table 1.

Definition of serum anion gap in major textbooks and web resources

SourceReferenceDefinition (mEq/L)Comments
Fluid, Electrolyte and Acid-Base Physiology, 4th Ed. Halperin et al. (9)Mean 12±2; presumed range, 8–16Values to be adjusted for prevailing serum albumin concentration
Clinical Physiology of Acid-Base and Electrolyte Disorders, 5th Ed. Rose (10)Range 7–13; 3–11 with ion-selective electrodesValues to be adjusted for prevailing serum albumin concentration; different values reflect different laboratory methods for measurement
Goldman’s Cecil Medicine, 24th Ed.Seifter (11) Approximate value 10–12No comment about correction for serum albumin
Textbook of Nephrology, 3rd Ed.a Salem and Batlle (8)10–12; 6–10 with ion-selective electrodesValues to be adjusted for prevailing serum albumin concentration
Brenner and Rector’s The Kidney, 8th Ed. Dubose (12)Mean 9±3; presumed range, 3–15Values to be adjusted for prevailing serum albumin concentration;
Murray and Nadel's Textbook of Respiratory Medicine, 5th Ed. Effros and Swenson (13)Range, 8–16Values to be adjusted for prevailing serum albumin concentration
UpToDate 2013 Emmett (14)Range, 7–13; 3–9 with ion-selective electrodesValues to be adjusted for prevailing serum albumin concentration
Henry’s Clinical Diagnosis and Management by Laboratory Methods, 22th Ed. Oh (15)Approximate 12; range, 8–16Values to be adjusted for prevailing serum albumin concentration
  • a Discussion from third edition chosen because discussant in fourth edition, T.D. Dubose, wrote on the topic in other books and is cited.