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Transfusion Service

(P-TS-88) Refining Platelet Transfusion Refractoriness Management: A Retrospective Evaluation of Testing

Sunday, October 20, 2024
12:00 PM - 1:00 PM  
Background/Case Studies: Platelet transfusion refractoriness (PTR) has multiple etiologies, including both immune and non-immune causes. The most common immune etiologies relate to human leukocyte antigen (HLA) or human platelet antigen (HPA) antibodies. Each hospital has its own policy to evaluate PTR. This quality improvement study focuses on evaluating our institution’s PTR management strategy.

Study

Design/Methods:

In this retrospective cross-sectional study, we evaluated PTR consults received by the transfusion medicine service from October 2022- March 2024. Patient demographics, obstetrical history, red blood cell (RBC) alloantibodies, ELISA indirect antibody test (screens HPA and HLA class I antibodies), FlowPRA (screens HLA class I antibodies), and platelet crossmatching solid phase red cell adherence assay, were recorded from patients’ chart.

Results/Findings:

A total of 56 patients (35 males) with mean age of 57 years were included. Five were suspected of having immune thrombocytopenic purpura. Twenty out of 21 females had a history of pregnancy.

Eleven patients had a positive ELISA indirect antibody (3, HLA; 2, HPA; 6, both HLA and HPA).

Twenty-seven patients had a positive FlowPRA screen (range 4-99% PRA). Of these, 13 were highly sensitized ( >90% PRA), and 9 had positive HLA antibodies by indirect ELISA assay (33% sensitivity).

Twenty-six patients had incompatibility with random donor platelets (crossmatch test). Neither ELISA nor FlowPRA was positive for all patients with incompatible crossmatch results (Table 1).

Six patients with a positive FlowPRA screen (range 4- 47% PRA) had no incompatibility with platelet crossmatching and a negative ELISA indirect antibody.

All patients received RBC transfusion. Six patients had RBC alloantibodies, all with a positive FlowPRA screen and some degree of incompatible crossmatch results.

Conclusions:

As a result of this study, our PTR work-up has been modified to 1) platelet crossmatching, and 2) FlowPRA HLA antibody screening. The ELISA indirect antibody test, which lacks sensitivity, has been removed from our algorithm since the results didn’t affect the final platelet recommendations of our original PTR strategy. Based on the results of platelet crossmatching and FlowPRA antibody, the transfusion team recommends crossmatched platelets, HLA matched platelets, or type-specific platelets for future transfusions.