Platelet Transfusion - the Art and Science of Compromise

Abstract

Many modern therapies depend on platelet (PLT) transfusion support. PLTs have a 4- to 7-day shelf life and are frequently in short supply. In order to optimize the inventory PLTs are often transfused to adults without regard for ABO compatibility. Hemolytic reactions are infrequent despite the presence of ‘high titer' anti-A and anti-B antibodies in some of the units. Despite the low risk for hemolysis, some centers provide only ABO identical PLTs to their recipients; this practice might have other beneficial outcomes that remain to be proven. Strategies to mitigate the risk of hemolysis and the clinical and laboratory outcomes following ABO-matched and mismatched transfusions will be discussed. Although the PLTs themselves do not carry the D antigen, a small number of RBCs are also transfused with every PLT dose. The quantity of RBCs varies by the type of PLT preparation, and even a small quantity of D+ RBCs can alloimmunize a susceptible D- host. Thus PLT units are labeled as D+/-, and most transfusion services try to prevent the transfusion of D+ PLTs to D- females of childbearing age. A similar policy for patients with hematological diseases is controversial, and the elements and mechanisms of anti-D alloimmunization will be discussed.

Clinical outcomes among low‐titer group O whole blood recipients compared to recipients of conventional components in civilian trauma resuscitation

“…These data suggest that the transfusion of incompatible plasma does not adversely affect a civilian trauma patient's clinical cours; however, LTOWB was not included in this study, hence its effect on clinical outcomes remains to be demonstrated in the civilian population. In addition, many of the PLT units that are transfused in the United States contain incompatible plasma, and the incidence of hemolysis is rare …”

Evaluating safety and cost‐effectiveness of platelets stored in additive solution (PAS‐F) as a hemolysis risk mitigation strategy

“…Mitigation strategies used by different facilities include provision of ABO‐compatible plasma products, physician notification, volume reduction, washed platelets, antibody screening for high‐titer ABO antibodies, pooled platelets of assorted ABO donor types, and limited transfusions of out‐of‐group plasma products. The risk of a clinically significant acute hemolytic transfusion reaction associated with group O donor platelets transfused to non–group O recipients is relatively low, estimated to be about 1 in 9000 (0.01%) in one study and 0.05% in another study . These reactions are likely rare due to the neutralization of the anti‐A or anti‐B antibodies by the recipient's soluble or endothelial‐based A and B antigens and/or the dilution of the incompatible ABO antibodies in the recipient's plasma volume.…”

Low titer A plasma in three AB patients for therapeutic plasma exchange

“…The observation that AB type TTP patients did not experience any clinical or laboratory exacerbation of hemolysis when a combination of AB and low titer A plasma was used is not surprising. Transfusion of ABO incompatible platelets is a common practice in medicine; hemolysis events from this ABO‐minor incompatibility is very rare and is further reduced when O group titered platelets are used . Group A plasma has been safely used in bleeding trauma patients and “Safety of the use of group A plasma in trauma: the STAT study” showed no difference in clinical outcomes between ABO identical group (A type patients that received A plasma) and ABO minor incompatible group (B/AB patients that received A plasma) .…”