Related Experiment Video
Updated: Jan 15, 2026

Functional Assessment of Intestinal Tight Junction Barrier and Ion Permeability in Native Tissue by Ussing Chamber Technique
Published on: May 26, 2021
A Quick Reference on Anion Gap and Strong Ion Gap
1Servei d'Urgències i Medicina Intensiva (SUMI), Fundació Hospital Clínic Veterinari-UAB, Bellaterra, Barcelona.
Abstract:
Metabolic acid-base disorders frequently occur in emergency and critically ill patients. Recognizing these disturbances can be challenging, particularly when multiple acid-base imbalances coexist within a single patient. The anion gap (AG) and strong ion gap (SIG) are valuable calculations that help identify complex metabolic acid-base disturbances associated with unmeasured anions. This review provides definitions, reference values, indications, limitations, and guidelines for interpreting AG and SIG changes in clinical settings.
Related Concept Videos
Ionic Strength: Overview
Ion-Exchange Chromatography
Ion Exchange
Acid/Base Strengths and Dissociation Constants
Common Ion Effect
Ions as Acids and Bases
Salts are ionic compounds composed of cations and anions, either of which may be capable of undergoing an acid or base ionization reaction with water. Aqueous salt solutions, therefore, may be acidic, basic, or neutral, depending on the relative acid-base strengths of the salt’s constituent ions. For example, dissolving the ammonium chloride in water results in its dissociation, as described by the equation:

