Three Cases Highlighting Three Potential Pitfalls in the Platelet Refractory Workup

Abstract Introduction/Objective Platelet refractory (PR) patients do not achieve expected post-transfusion platelet counts. We investigate such with a count, indirect Antibody Screen (ind-PAS), Class I HLA (HLA-Ab) testing, and crossmatch (PXM). The following three cases highlight potential pitfalls of laboratory investigations for PR patients. Methods/Case Report Case #1 (57-year-old male AML) revealed discrepant predicted observed donor compatibility. testing demonstrated no glycoprotein antibodies HLA-ab to B13, corresponding 4% calculated PRA (CPRA), indicating 96% However, PXM that the patient was compatible 11/14 (79%) screened donors. Communication reference two incompatible units were ABO incompatible. #2 (27-year-old female aplastic anemia) is highly sensitized (99% CPRA). compatibility 1/14 donors; however, she failed respond donor. To this poor response, patient’s plasma tested against Neat serum all donors, whereas 1:8 dilution resulted in positive crossmatches half false negative are likely explained by prozone setting high burden. #3 (79-year-old discrepancy between ind-PAS (PakPlus, Immucor), which HLA-ab, specificity (LABScreen, OneLambda), antibodies, 38% CPRA. Per package insert, sensitivity assay 85%-91% compared selected tests; other sources have lower 68%. Results (if Study enter NA) NA. Conclusion importance investigating incongruent results. Cases demonstrate PXM: incompatibility can result false-negative occur reveals knowing test’s limitation, especially sensitivity. Centers only perform may miss detection.