Hemolysis can cause falsely elevated potassium in a sample because:

• A. Red cell potassium is released when cells lyse
• B. Potassium binds to plasma proteins
• C. Water loss concentrates potassium
• D. Air exposure oxidizes potassium

Answer: (A)

The main concept is that potassium is predominantly inside red blood cells, so when cells lyse, their potassium is released into the surrounding plasma or serum. Red blood cells carry a high intracellular potassium concentration, while the extracellular fluid has much lower levels. If the sample is hemolyzed during collection or processing, potassium from the ruptured cells adds to the plasma, making the measured potassium appear higher than it actually is in the patient’s blood.

That’s why hemolysis in a sample can lead to a falsely elevated potassium result. The other ideas—potassium binding to plasma proteins, concentrating from water loss, or oxidation by air exposure—do not explain the abrupt rise seen with hemolyzed samples.