Abstract Number: LPB0126
Meeting: ISTH 2021 Congress
Background: Light transmission aggregometry (LTA) is the gold standard to diagnose inherited platelet function disorders (IPFD) and von Willebrand disease type 2B (VWD2B). LTA is a time-consuming method requiring large blood volumes. In contrast, whole blood impedance aggregometry (WBIA) is a quicker and simpler method requiring limited volume of blood.
Aims: We evaluate the ability of WBIA to identify already diagnosed IPFD and VWD2B. We also compare the results of both methods in patients referred for unexplained bleeding tendency.
Methods: One hundred sixty patients were studied (Table 1). LTA was performed on platelet-rich plasma according to international recommendations (SSC/ISTH). WBIA was performed on hirudin-anticoagulated blood using the Multiplate® analyzer (Roche) according to manufacturer’s instructions. Normal ranges were calculated in 30 healthy individuals.
|N=||Gendre (F/M)||Age (years±SD)||Platelet Count (x 109L-1±SD)|
|VWD type 2B||14||9/5||36±21||146±83|
|Gray Platelet Syndrome
|Unexplained bleeding tendency||83||62/21||29±18||234±90|
Results: WBIA correctly diagnosed all patients with Glanzmann Thrombasthenia, Bernard-Soulier Syndrome, platelet-type VWD as well as 13/14 patients with VWD2B, whatever the platelet count. Thrombocytopenic patients with MYH9-related disease had sub-normal results with all agonists. However, VWD patients were poorly detected (15/29, 51.7%). Among 83 patients referred for unexplained bleeding tendency, WBIA and LTA gave concordant results in 48/83 (57.8%) patients: 29 had normal results and 19 had abnormal results with one or more agonists using both methods. Discrepant results were observed in 35/83 (42.1%) patients (Table 2).
Conclusions: Our study shows that WBIA 1/ is able to properly characterize patients with severe IPFD and VWD2B, including those with thrombocytopenia 2/ is less sensitive/specific in detecting mild platelet abnormalities compared to LTA. The negative predictive value of 0.85 suggests that it might be a useful quick and easy-to use screening test while it cannot avoid further testing by LTA in patients with unexplained bleeding tendency.
To cite this abstract in AMA style:Ellouze S, Lavenu-Bombled C, Perrier-Cornet A, Combe S, Blandinieres A, Lambert T, D'Oiron R, Proulle V. Whole Blood Impedance Aggregometry: A Usefool Tool but Still Not the Gold Standard [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/whole-blood-impedance-aggregometry-a-usefool-tool-but-still-not-the-gold-standard/. Accessed October 1, 2023.
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