The effect of timing of gamma-irradiation on hemolysis and potassium release in leukoreduced red cell concentrates stored in SAGM.

While irradiation of red cell concentrates (RCC) prevents graft-versus-host disease in susceptible transfusion recipients, it also damages red blood cells (RBC). To understand the ability of irradiation regulations to prevent transfusion of inferior units, we irradiated 980 RCC in saline-adenine-glucose-mannitol (SAGM) using various combinations of pre-irradiation age and post-irradiation storage times, and measured hemolysis and extracellular potassium levels. We observed unacceptably high hemolysis (>0·8%) in some RCC and elevated extracellular potassium levels in all gamma-irradiated RCC. This suggests that more restrictive storage times should be considered for RCC in SAGM.