The Significance of Plasma Potassium Level in Pseudohyperkalemia with Thrombocytosis

Lee, Hwa Yeon; Son, Jin A; Ko, Jae Wook; Kim, Jae Yoon; Ahn, Don Hee

Abstract

PURPOSE: As blood coagulates, potassium is released from cells, causing the concentration of potassium in serum to be slightly higher than that of plasma. We measured serum and plasma potassium levels simultaneously to evaluate the significance of plasma potassium especially in the patients with thrombocytosis.
METHODS
The study was designed into two steps. To determine the relationship between platelet count and serum potassium level, the subjects of the first study were 140 children admitted to the National Medical Center (NMC) from January 1996 to June 1997. To determine the significance of plasma potassium level in pseudohyperkalemia with thrombocytosis, the subjects of the second study were 80 children admitted to the NMC from June 1997 to June to 1998. All of them are 1 month to 14 years old.
RESULTS
1) There was no relationship between the platelet count and serum potassium levels in the control group with platelet count from 150x109/L to 400x10(9)/L (r=0.07), but there was significant relationship in the group with platelet count above 400x10(9)/L (r=0.41, P<0.01). 2) As platelet counts increased, the differences between the serum and plasma potassium concentration increased (r=0.518, P<0.01).
CONCLUSION
The clinician should pay attention to the possibility of the pseudohyperk alemia when there is thrombocytosis with hyperkalemia without specific hyperkalemic symptoms or EKG changes. Plasma potassium level will be helpful for the accurate assesment of potassium concentration.