Potassium in extreme leukocytosis

Q: Severe leucocytosis may cause? (select one)

A) Pseudo-hyperkalemia

B) Pseudo-hypokalemia

C) Either A or B

Answer: C

Conventional teaching is to associate pseudo-hyperkalemia with extreme leucocytosis due to hemolysis in the sample. The objective of this question is to highlight that either Pseudo-hypo or hyperkalemia can occur in severe leucocytosis. 

The mechanism of pseudo-hypokalemia is the increased uptake of plasma potassium by high leukocytes in the sample. If Pseudo-hypo or hyperkalemia is suspected, true potassium level can be measured by sending a specimen quickly and requesting to run the sample in separated plasma or serum.

#electrolytes

#lab-medicine

Reference:

Colussi G, Cipriani D. Pseudohyperkalemia in extreme leukocytosis. Am J Nephrol. 1995;15(5):450-2. doi: 10.1159/000168883. PMID: 7503149.