Associations between ABO non‐identical platelet transfusions and patient outcomes—A multicenter retrospective analysis

Abstract

Background: Due to platelet availability limitations, platelet units ABO mismatched to recipients are often transfused. However, since platelets express ABO antigens and are collected in plasma which may contain ABO isohemagglutinins, it remains controversial as to whether ABO non-identical platelet transfusions could potentially pose harm and/or have reduced efficacy.Study Design and Methods: The large 4-year publicly available Recipient Epidemiology and Donor Evaluation Study-III (REDS-III) database was used to investigate patient outcomes associated with ABO non-identical platelet

Reply: ABO nonidentical platelet transfusions and mortality

“…We thank Blumberg et al for their letter on our recent paper on ABO nonidentical platelet transfusions and mortality. 1 Regarding their questions about the use of hospital-days and Cox regression, we sought to investigate the role of multiple transfusions given to an individual patient by focusing on a time-varying measure of exposure to identical only, major, minor, or bidirectional mismatched platelets as opposed to a "switch on" with the first nonidentical exposure that does not take into account the type and number of transfused products. As illustrated in Figure 2 in our paper, person-time was allocated in a time-dependent manner upon receipt of a subsequent platelet transfusion, with each person-time interval categorized in an escalating classification from identical only to major or minor to bidirectional.…”