An optimized procedure for Luminex-based human platelet antigen-specific antibody screening and identification (PakLx assay) with a cost-effective approach and improved sensitivity

Background and Objectives: Detection of anti-platelet antibodies is required for the diagnosis of foetal/neonatal alloimmune thrombocytopaenia. The most commonly used methods for anti-platelet antibody detection are the monoclonal antibody-specific immobilization of platelet antigens (MAIPA) and the Luminex bead assay (PakLx). However, for economic reasons, the use of the PakLx assay is limited.Materials and Methods: In the present study, we evaluated the performance of an optimized protocol based on a half-volume of PakLx reagents. We compared two alternative procedures: one with a half-volume of all components including patient samples, and another based on a half-volume of reagents but a standard volume of patient sample.Results: Our results obtained with a panel of 67 samples demonstrate improved sensitivity when using a standard sample volume.Conclusion: In the event of an inconclusive result with this optimized protocol (e.g., incomplete panel of positive Luminex beads), we recommend testing the sample with an alternative protocol (e.g., MAIPA or the original PakLx protocol).