Abstract Number: PB0574
Meeting: ISTH 2020 Congress
Background: The T-TAS01 PL assay is a novel in vitro diagnostic system that passes whole blood through a collagen-coated microcapillary bed at arterial shear stress to measure the platelet thrombus formation process. The test is used to assess overall primary hemostatic function. Results are reported as the area under the pressure-time curve (AUC).
Aims: To validate the diagnostic performance of the T-TAS01 PL assay using a pre-specified AUC< 260 cutoff in subjects with confirmed normal primary hemostatic function and in subjects with von Willebrand disease (vWD) and Glanzmann's thrombasthenia (GT).
Methods: Healthy subjects and subjects with confirmed vWD or GT were enrolled according to an IRB-approved protocol at five investigational sites. Blood samples were collected into vacuum tubes containing benzylsulfonyl-D-Arg-Pro-4-amidinobenzylamide (BAPA), a thrombin and factor Xa inhibitor. Healthy subjects were screened for possible primary hemostasis defects and confirmed to have normal primary hemostatic function.
Results: 170 subjects were enrolled. The T-TAS01 PL AUC< 260 cutoff was 96% specific, and 72% and 100% sensitive for abnormal primary hemostatic function in vWD and GT, respectively. AUC results were highly correlated with vWF antigen, vWF activity, and factor VIII activity levels (Spearman's rho = 0.55, 0.83, and 0.71, respectively, all p < 0.01). vWD patients with AUC>260 had either normal PFA-100 results, or vWF antigen, vWF activity, and FVIII:C results that were above levels typically associated with vWD, suggesting that these subjects had mild vWD and did not have significantly impaired primary hemostatic function.
Conclusions: The T-TAS01 PL assay is highly sensitive and specific for impaired primary hemostatic function, and AUC results decrease in proportion to the severity of impairment. T-TAS01 PL assay measurements may be useful for the assessment of overall primary hemostatic function in patients with bleeding tendencies or defects in primary hemostatic function.
|Group||N||Mean Age||% Female||Mean AUC||% < 260 AUC|
|vWD Type 1||12||42||83.3%||247.9||50.0%|
|vWD Type 2||10||49||80.0%||65.5||90.0%|
|vWD Type 3||3||59||33.3%||28.1||100.0%|
To cite this abstract in AMA style:Dahlen J, Lentz SR, Wu AHB, Fiore M, Leavitt A, Gurbel P, Ong C-, Bliden K, Peters T, Tantry U, Hosokawa K. Clinical Validation of the T-TAS 01 PL Assay in Patients with von Willebrand Disease and Glanzmann´s Thrombasthenia [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/clinical-validation-of-the-t-tas-01-pl-assay-in-patients-with-von-willebrand-disease-and-glanzmanns-thrombasthenia/. Accessed September 21, 2023.
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