Packed Red Blood Cell (PRC) is a blood component obtained after most of the plasma is separated from Whole Blood (WB) by various methods and has a hematocrit value of 80%. During storage time, blood cells undergo metabolic changes, so in vitro storage must be considered in an effort to reduce changes that occur in blood cells, because the atmosphere is really different from in vivo. Objective: This study aims to determine the effect of the long storage time of blood on the potassium levels of patients receiving Packed Red Cell (PRC) transfusion in Haji Adam Malik General Hospital, Medan. Methods: Analytical study with a pretest-posttest group design to determine the effect of blood storage time on changes in blood potassium levels after Packed Red Cell (PRC) transfusion in Haji Adam Malik General Hospital, Medan

Keywords : Packed Red Blood Cell, Potassium, Storage Time