Assessment of Bleeding Phenotype in Hemophilia Α By a Novel Point-of-Care Global Assay

Introduction: Patients with Hemophilia A have considerable phenotypic heterogeneity with respect to clinical severity based on their baseline factor levels. As clinical bleeding risk is helpful to individualize factor replacement therapy in hemophilia patients, previous studies have utilized direct and indirect methods of thrombin generation to classify individual bleeding phenotypes, however, with variable results. An easy to use, point-of-care, global assay to assess bleed phenotype, can be a useful tool in the clinical setting to determine intensity of prophylaxis therapy for patients with hemophilia. We have previously introduced a novel, point-of-care (POC), dielectric microsensor, ClotChip, and demonstrated its sensitivity to factor replacement in patients with severe hemophilia A. We aim to further test the ability of ClotChip in assessment of a bleeding phenotype, as described by a bleeding score, in patients with hemophilia A. Methods: After IRB approval, 28 patients with hemophilia A of varying severity and well-characterized bleeding history, were enrolled in this study at the time of trough factor levels. The bleeding history was extracted from patient charts and included number of bleeds (joint and soft-tissue), annual factor usage in terms of units/kg, and number of target joints. These parameters were used to generate a bleeding score (range: 0 - 24), and patients were divided in to 2 categories with scores between 0 - 12 (n=14) and > 12 (n=14). Healthy volunteers (n=17) were accrued as controls. Whole blood samples were obtained by venipuncture into collection tubes containing 3.2% sodium citrate. Samples were then tested with the ClotChip within 2 hours of collection. ClotChip is based on the electrical technique of dielectric spectroscopy (DS) and features a low-cost (material cost Results: ClotChip exhibited a mean Tpeak of 2186s ± 1560s for hemophilia patients in the group with higher bleeding scores (i.e. score >12), a mean Tpeak of 931s ± 496s for the group with lower bleeding scores (i.e. score Conclusions: Our studies suggest that a novel dielectric microsensor (ClotChip) could be useful in assessing bleeding phenotype in hemophilia A patients, allowing rapid assessment of hemostasis using a miniscule amount of whole blood ( Download : Download high-res image (691KB) Download : Download full-size image Disclosures Maji: XaTek, Inc: Patents & Royalties: 9,995,701. Suster: XaTek, Inc: Consultancy, Patents & Royalties: 9,995,701. Mohseni: XaTek, Inc: Consultancy, Patents & Royalties. Ahuja: XaTexk Inc.: Consultancy, Patents & Royalties, Research Funding; Rainbow Children's Foundation: Research Funding; Bayer: Consultancy; Biovertiv Sanofi: Consultancy; Genentech: Consultancy.