Pseudohyperkalemia: A new twist on an old phenomenon.

Severe hyperkalemia is a potentially life-threatening condition requiring immediate medical intervention. Pseudohyperkalemia can be misleading and result in incorrect interpretation and inappropriate patient management. Immediate recognition and appropriate interpretation of pseudohyperkalemia, on the other hand, prevents misdiagnosis and unnecessary intervention. Pseudohyperkalemia is induced by hemolysis and excessive leakage of potassium from cells during or after blood collection. It has been increasingly seen in many hematological disorders such as leukocytosis and thrombocytosis. Reverse pseudohyperkalemia has recently been reported in leukemic patients in whom the plasma potassium levels are greater than the serum potassium levels because of heparin-induced cell membrane damage. Although pseudohyperkalemia has long been recognized and understood, it continues to be misinterpreted. To improve patient care, an algorithm for investigation of pseudohyperkalemia and preventive measures should be established and implemented in the clinical laboratory.