Provision of HPA-1a (Pl^A1)-negative platelets for neonatal alloimmune thrombocytopenia: screening, testing, and transfusion protocol

HPA-1a-negative platelet products are not routinely available for newborns with alloimmune thrombocytopenia. In this article we describe a program established to identify normal pheresis donors who are HPA-1a-negative and to organize their future donations so that our regional blood center would always have an HPA-1a-negative platelet product available. The solid phase red cell adherence assay was used for initial screening of platelet pheresis products. HPA-1a-negative donors were confirmed with the platelet suspension immunofluorescence test using three anti-HPA-1a sera. Screening of 2600 platelet-pheresis donor samples identified 40 HPA-1a-negative donors. Of these, 36 are active and are coded for recognition on the daily pheresis inventory sheet. Theoretically, assuming four donations per year and donors’ cooperation with scheduling, these 36 donors would enable us to have at least one HPA-1a-negative product available every day. In addition, a decision tree for patient management using platelet serology and availability of HPA-1a-negative products was developed. The GTI-PAK™12 is the major technique used for serologic screening of mothers of patients thought to have neonatal alloimmune thrombocytopenia. By screening pheresis donors and developing a clinical decision tree, HPA-1a-negative products, a rare resource, can be fully utilized. Immunohematology 1999;15:71–74.