ABSTRACT
Potassium is the major intracellular cation. A 70kg adult has 3500mmol potassium, of which about 60mmol (2%) is extracellular. The normal extracellular concentration ranges from 3.5 to 5.1mmol l−1. The intracellular concentration is 150mmol l−1. Large changes in total body potassium can occur without significant effect on plasma potassium concentration.
