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Analysis of ABO nonidentical platelet transfusions in relation to patient outcomes

It is estimated that 40 percent of platelet transfusions in the United States are ABO mismatched to the recipient. In the United States, platelets are primarily collected by apheresis, which helps limit the amount of incompatible plasma transfused to the recipient when using ABO-mismatched platelets. Reasons for transfusing ABO minor and major incompatible platelets include supply-and-demand issues, limited platelet shelf life, and variability in institutional policies and practices. Major mismatch platelets are when the donor platelets carry A/B antigen that is not compatible with the recipient ABO type—for example, type A donor and type O recipient. Minor mismatch is when the platelet plasma is not compatible with the recipient ABO type—for example, type O platelet donor and type A recipient. Studies have examined outcomes for ABO-mismatched platelets, yet guidelines vary significantly. The authors conducted a study using the large four-year publicly available Recipient Epidemiology and Donor Evaluation Study-III database to identify associations between ABO nonidentical platelet transfusions and the clinical outcomes of mortality, sepsis, and thrombosis, with the intent of helping to shape future platelet transfusion guidelines. They investigated patient outcomes associated with ABO nonidentical platelets from January 2013 through December 2016. There were 26,902 encounters identified among the study cohort of 21,176 patients, who received 79,473 platelet transfusions. An encounter was defined as an inpatient receiving a platelet transfusion. Platelet transfusions were defined as ABO identical, major mismatched, minor mismatched, or bidirectional mismatched (donor platelets and plasma are not compatible with the recipient—for example, type A donor and type B recipient). After the statistical analysis was adjusted for possible confounding factors, the data showed no statistically significant association between ABO nonidentical platelet transfusion and increased risk of mortality. However, when diagnostic category and recipient ABO group were examined, mortality for major mismatched transfusions in two of the eight subpopulations increased. These subpopulations were hematology/oncology blood groups A and B (but not group O) recipients with a hazard ratio (HR) of 1.29 and intracerebral hemorrhage group O (but not groups A and B) recipients with a HR of 1.75. The authors also found that major mismatched transfusions were associated with increased odds of receiving additional platelet transfusions each day through day five, regardless of the recipient’s ABO group. They concluded that prospective studies are needed to determine which patient populations may benefit from receiving only ABO-identical platelets and that ABO-identical platelet products minimize patient exposure to additional platelet doses.

Bougie DW, Reese SE, Birch RJ, et al. Associations between ABO non-identical platelet transfusions and patient outcomes—a multicenter retrospective analysis. Transfusion. 2023;63:960–972.

Correspondence: Dr. Daniel W. Bougie at dwbougie@versiti.org