STUDIES ON THROMBOCYTOSIS. I. HYPERKALEMIA DUE TO RELEASE OF POTASSIUM FROM PLATELETS DURING COAGULATION1

Abstract

Elevated serum K concentrations were noted in 4 of 13 patients with thrombocytosis (one to several million platelets per mm3 blood) in the absence of symptoms or signs of hyperkalemia. This represented a spurious hyperkalemia due to release of K from the platelets during coagulation, since serum prepared from platelet-free plasma had a normal K concentration. Therefore, the circulating plasma K was normal. In the most striking case, serum from clotted whole blood or platelet-rich plasma had a K concentration of 7.2 to 9.6 meq/1 and that from platelet-free plasma 4.2 to 5.4. Coagulation, incubation of clotted plasma, and disruption of platelets by freezing were associated with additional increments of K from platelets. Mean K of normal platelets was 69.1 meq/kg (wet weight) or 86.4 meq/1 platelet water. Platelet K was normal in chronic myeloid leukemia and slightly increased in polycythemia vera and myeloid metaplasia. This increase, however, was insufficient to account for the spurious hyperkalemia which was mainly due to an increased platelet mass per unit volume of blood of plasma. Platelet water was about 80%. Platelet concentrations of K and Na approximated those of the red cell.