Reverse pseudohyperkalemia in heparin plasma samples from a patient with chronic lymphocytic leukemia

Objectives: To investigate the spurious high potassium results in heparin plasma. Design and methods: Potassium values from heparin plasma, serum, and whole blood in a patient with chronic lymphocytic leukemia were determined and compared on chemistry and blood gas analyzers. Results: Potassium levels were strikingly elevated in heparin plasma compared to serum or whole blood in which the potassium levels were surprisingly normal. Conclusions: The phenomenon of reverse pseudohyperkalemia should be publicized. (C) 2011 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.