Background/Case Studies: Immune destruction of platelets can occur in patients with hematologic disorders (e.g., leukemias, systemic lupus erythematosis, other “collagen-vascular” diseases), viral infections, or pregnancy or transfusion related alloimmunization. To avoid such reactions, in vitro antibody detection tests (e.g., antibody screening or crossmatching) are standard pre-transfusion safety measures. Immucor’s Capture-P® solid phase system uses immobilized platelets to detect IgG antibody activity in patient blood specimens and has been on the market since 1986 for manual platelet antibody detection. However, manual methods are more labor-intensive and error-prone than automated methods. Currently, there are no automated options for platelet crossmatch and antibody screening on the market. To enable customers to automate the qualitative detection of IgG platelet antibodies with the Capture-P® solid phase system, Werfen has developed an automated Capture-P® assay for the NEO Iris®/NEO® (v2.0) automated systems.
Study
Design/Methods: Werfen has developed a fully automated assay to detect IgG platelet antibodies to selected platelets using SPRCA technology on the NEO Iris®/NEO® (v2.0) platforms. This study used a method comparison testing approach performed at three sites (2 external and 1 internal site) to test 601 clinical samples. Each site provided the pre-defined number of leftover, de-identified donor, patient, and neonatal samples. All results were analyzed to determine concordance between the manual and automated Capture-P® assays. Discrepant results underwent further evaluation with manual Capture-P® Ready-Screen®.
Results/Findings: Method comparison testing was performed at three sites (2 external and 1 internal). A total of 601 samples were tested using the Capture-P® assay on an automated NEO Iris® instrument and the manual Capture® workstation and the results were compared. Donor and patient samples were provided by each site. The internal site also provided 5 neonatal samples. 507 valid results were analyzed (94 samples were excluded for protocol deviations, invalid results, or no interpretation). The initial PPA was 70.77% and the one-sided Clopper Pearson exact 95% lower confidence limit for the NPA was 98.26%. After resolution with Capture-P® Ready-Screen®, 20 out of 22 discrepant results agreed with the automated results. The final PPA was 97.96% and the one-sided Clopper Pearson exact 95% lower confidence limit for the NPA was 98.97%.
Conclusions: The automated Capture-P® screening assay on the NEO Iris®/NEO® (v2.0) automated blood bank analyzers enables efficient and accurate detection of IgG anti-platelet antibodies and shows equivalent or better performance to manual Capture-P® solid phase system. This represents the first and only automated platelet crossmatch technology for bloodbanking applications.
