Falsely elevated serum or plasma potassium level can be the result of mechanical injury to blood cells. We describe pseudohyperkalaemia caused by pneumatic tube transport of blood specimens from a patient with leukaemia. Clinicians should be aware of this possibility when interpreting the clinical significance of hyperkalaemia. In leukaemic patients, pneumatic tube transport of blood specimens for potassium analysis should be avoided.
Keywords: Blood specimen collection; Hyperkalemia; Leukemia, myeloid, acute.