Hyperkalemia Associated with the Myeloproliferative Disorder

Elevated serum potassium levels unassociated with manifestations of hyperkalemia have been observed in patients with thrombocythemia associated with the myeloproliferative disorder.¹⁻³Studies indicate that potassium released from platelets during the process of blood coagulation is responsible, since serum prepared from platelet-free plasma has a normal potassium concentration. "Spurious hyperkalemia" has been suggested as a term for this syndrome.³We wish to reemphasize these findings with additional observations. Results and Comment Table 1 lists the clinical and laboratory data in a group of patients with elevations of leukocytes, erythrocytes, and platelets alone or in various combinations. Significant elevations of serum potassium levels above the normal level of 5 mEq. per liter were noted in Patients 1, 4, 5, 6, 7, 8, 9, and 14. In each of these patients there was a significant elevation of the platelet count. In the absence of thrombocythemia, elevations of the leukocyte or erythrocyte