title: Transfusion efficacy of apheresis platelet concentrates irradiated at the day of transfusion is significantly superior compared to platelets irradiated in advance.
abstract: BACKGROUND
  Gamma irradiation is currently the standard care to avoid transfusion-associated graft-versus-host disease. Guidelines on gamma irradiation of blood components state that platelets (PLTs) can be irradiated at any stage in their 5-day storage and can thereafter be stored up to their normal shelf life of 5 days after collection. In this study, we explored whether the timing of irradiation has an effect on transfusion efficacy of apheresis PLT concentrates (APCs).
  
  
  METHODS
  Based on the 1-hour percent PLT recovery (PPR1h), transfusion efficacy of 1,000 eligible APCs transfused to 144 children were evaluated retrospectively. PPR1h was compared in transfused APCs irradiated at the day of transfusion and APCs irradiated in advance.
  
  
  RESULTS
  In univariate analysis, transfusion efficacy of APCs irradiated in advance was significantly lower than that of APCs irradiated at the day of transfusion (mean PPR1h 27.7 vs. 35.0%; p = 0.007). This was confirmed in multivariate analysis (p = 0.030). Compared to non-irradiated APCs, transfusion efficacy of APCs irradiated at the day of transfusion was not significantly inferior (mean difference -2.8%; 95% CI -6.1 to 0.5%; p = 0.092), but APCs irradiated in advance were clearly less efficient (mean difference -8.1%; 95% CI -12.2 to -4.0%; p < 0.001).
  
  
  CONCLUSIONS
  Our data strongly support that APCs should not be irradiated in advance, 1.e., ≥24 h before transfusion.
authors: Department of Pediatrics, University of Bern, Bern, Switzerland.
authors: Friedgard
authors: F
authors: Julmy
authors: Department of Pediatrics, University of Bern, Bern, Switzerland.
authors: Roland A
authors: RA
authors: Ammann
authors: Blood Transfusion Service of the Swiss Red Cross, Bern, Switzerland.
authors: Stefano
authors: S
authors: Fontana
authors: Department of Hematology, University of Bern, Bern, Switzerland ; Blood Transfusion Service of the Swiss Red Cross, Bern, Switzerland.
authors: Behrouz Mansouri
authors: BM
authors: Taleghani
authors: Department of Pediatrics, University of Bern, Bern, Switzerland.
authors: Andreas
authors: A
authors: Hirt
authors: Department of Pediatrics, University of Bern, Bern, Switzerland.
authors: Kurt
authors: K
authors: Leibundgut
keywords: Gamma irradiation; Platelet concentrates; Platelet storage; Platelet transfusion