Pseudohyperkalemia Revisited: An Updated Review of a Foremost Preanalytical Error of Serum or Plasma Potassium Measurement in the Clinical Laboratory

Abstract

Background: Potassium is one of the most abundant cations in the human body. Increased plasma potassium concentration (hyperkalemia) is one of the most common electrolyte abnormalities in contemporary clinical practice. Moderate and severe hyperkalemia are potentially life-threatening conditions and constitute medical emergencies. Measured hyperkalemia may be true hyperkalemia or false hyperkalemia (pseudohyperkalemia). Pseudohyperkalemia is due to false elevation of measured potassium concentration in vitro and it is a fairly common source of preanalytical error of potassium determination in the clinical laboratory. OBJECTIVE: To review the general and recent concepts/mechanisms that underlie the phenomenon of pseudohyperkalemia in contemporary clinical practice. Methods: An up-to-date review of available literature and selected references on the phenomenon of pseudohyperkalemia, its causes, variants, mechanisms, clinical implications, identification, management, and prevention. Conclusion: Pseudohyperkalemia is a fairly common preanalytical error of potassium measurement in the clinical laboratory and a potential cause of misdiagnosis and unnecessary treatment of hyperkalemia. Exclusion of pseudohyperkalemia before the diagnosis of hyperkalemia (true hyperkalemia) is highly recommended.

Keywords

• hyperkalemia
• masked hypokalemia
• potassium
• pseudohyperkalemia
• true hyperkalemia