Hyperkalemia may be caused by each of the following EXCEPT

• A. Alkalosis
• B. Acute or chronic renal failure
• C. Hypoaldosteronism
• D. Sample hemolysis

Answer: (A)

Hyperkalemia occurs when potassium is not adequately excreted or is shifted from inside cells into the extracellular space. Acute or chronic renal failure reduces the kidneys’ ability to excrete potassium, leading to accumulation. Hypoaldosteronism decreases potassium secretion in the distal nephron, also raising serum potassium. Hemolyzed samples release potassium from red blood cells, producing a falsely elevated measured value. Alkalosis, on the other hand, drives potassium into cells, reducing serum potassium and tending toward hypokalemia, not hyperkalemia. So alkalosis is not a cause of hyperkalemia.