To the Editor:—
The communication, "Red Blood Cell Potassium: Therapeutic Implications," by Singer et al, which appeared in the Jan 4, 1964, issue of The Journal (187:24), raised questions which surely should be answered, since they have distinct clinical pertinence. The question of a relationship between potassium content of red blood cells (RBC) and that of other body cells is a matter of great interest because of the easy availability of RBC and the knowledge that serious disturbances in cell potassium content may impair intracellular metabolism and lead eventually to necrosis.Unfortunately, the authors used methodology which does not facilitate the procurement of precise data. Specifically, the indirect method they used for determining the RBC potassium content suffers the major disadvantage of cumulative errors, namely, that of combined errors regarding the plasma potassium, whole blood potassium, and the hematocrit determinations. This method has been commented on by Peters and