The Difference between Serum and Plasma Potassium

To the Editor: The importance of hypokalemia induced by diuretics used in the treatment of hypertension is a major topic of debate.1,2 Diuretic-induced hypokalemia has been held responsible for glucose intolerance, hypercholesterolemia, and ventricular arrhythmias, with a resultant increase in coronary mortality.3 Clinicians' concerns about diuretic-induced hypokalemia led to the dispensing of 7.5 million prescriptions for potassium preparations and 19 million for potassium-sparing diuretics in a recent year in the United States.4 Despite the need for accurate measurement of potassium concentrations, there are several circumstances wherein results may be misleading. Hemolysis is known to mask hypokalemia. The muscular activity.