A comparison of the effect of X and gamma irradiation on red cell storage quality

Background and Objectives Irradiation of red cell components is indicated for recipients at risk of transfusion-associated graft vs. host disease. Current technologies available comprise of a gamma (gamma) or an x source of radiation. The benefits of x vs. gamma include non-radioactivity and hence no decay of the source. We aimed to compare the effect of the two technologies on red cell component storage quality post-irradiation. Materials and Methods Paired units of red cell concentrates (RCC), neonatal red cell splits (RCS), red cells for intra-uterine transfusion (IUT) or neonatal exchange transfusion (ExTx) were either gamma- or x-irradiated. Units were sampled and tested for five storage parameters until the end of shelf life. Equivalence analysis of storage quality parameters was performed for pairs of the same components (RCC, RCS, IUT or ExTx) that were either gamma- or x-irradiated. Results Nearly all component comparisons studied showed equivalence between gamma and x irradiation for haemolysis, ATP, 2,3-DPG, potassium release and lactate production. The exceptions found that were deemed non-equivalent were higher haemolysis with x irradiation for ExTx, lower 2,3-DPG with x irradiation for RCS irradiated early and higher ATP with x irradiation for IUT. However, these differences were considered not clinically significant. Conclusion This study has demonstrated that a range of red cell components for use in different age groups are of acceptable quality following x irradiation, with only small differences deemed clinically insignificant in a few of the measured parameters.