Role of point-of-care arterial blood potassium in diagnosing pseudohyperkalemia

Hyperkalemia is a life-threatening emergency, but it needs to be differentiated from pseudohyperkalemia to avoid unnecessary treatment. We present a case of pseudohyperkalemia in a chronic lymphocytic leukemia patient with severe leukocytosis, highlighting the role of point-of-care potassium. Laboratory workup showed persistent hyperkalemia on analysis of venous blood samples even after treatment for hyperkalemia. Point-of-care potassium checks on whole arterial blood immediately after sampling were consistently in the normal range. Treatments for hyperkalemia were stopped to avoid life-threatening hypokalemia.