Laboratory testing for the diagnosis of immune-mediated thrombocytopenia

Alloantibodies directed against human platelet antigen (HPA) have been involved in the pathogenesis of immune-mediated thrombocytopenia, such as fetal/neonatal alloimmune thrombocytopenia (FNAIT), platelet transfusion refractoriness (PTR), and post-transfusion purpura (PTP). Therefore, for the diagnosis of these conditions, the detection and identification of the causative alloantibody is crucial. For many years, the methodologies for the detection of such antibodies were based on the use of intact platelets, however, the appropriate detection sometimes has been hampered due to the unique characteristics of the platelet membrane. In the recent years, an important progress of the serological methodologies has been observed. In this paper, we review the classical and the novel methodologies available for the detection and identification of HPA alloantibodies.