Evaluation of potassium values in a cancer patient population

Take-Home Message: A wide variety of clinical conditions are associated with potassium metabolism. It is important to recognize that factitious or pseudohyperkalemia is not uncommon in patients with cancer. These conditions are a result of marked leukocytosis or thrombocytosis associated with some cancers or as secondary to therapy. Methods: This small study assayed for potassium values using 37 pairs of serum and plasma samples for evaluation. Thirty-six pairs were drawn from outpatients scheduled for clinic visits, while 1 pair was from an inpatient with a known history of marked leukocytosis and thrombocytosis. Findings: Serum potassium values were greater than those obtained from plasma in average, and the difference was statistically significant. The presence of pseudohyperkalemia should be considered in any patient with marked leukocytosis or plasmacytosis in which the potassium values are obtained in the absence of corresponding clinical symptoms.