A comparative study of reducing the extracellular potassium concentration in red blood cells by washing and by reduction of additive solution

BACKGROUND: Extracellular potassium concentration (K+) increases in the supernatant of whole and packed red blood cell units (pRBCs) with duration of refrigerated storage in citrate‐phosphate‐dextrose‐adenine (CPDA‐1) and additive solution (AS). Studies have shown that to avoid hyperkalemia, washed pRBCs are preferred if relatively fresh pRBCs are not available. To determine whether a simpler procedure, AS reduction, results in lowering of K+ in pRBCs comparable to that achieved by washing, the K+ levels by both methods were compared.