Abstract Number: PB0630
Meeting: ISTH 2020 Congress
Background: The main problem of flow cytometry for platelet testing is the lack of reference intervals for markers on the platelet surface. Moreover, there are no criteria for the effectiveness of antiplatelet therapy when using this method as a diagnostic test.
Aims: To determine the reference intervals for markers of platelet functional activity among healthy donors by flow cytometry, as well as to determine the cut-off value for evaluating the dual antiplatelet therapy (DAT) effectiveness in patients with peripheral artery diseases (PAD).
Methods: The study included 29 patients (over the 40 years) with PAD and 120 healthy donors (18-65 year). All patients on day 14 of DAT (75mg clopidogrel+100mg ASA) were determined by the expression of P-selectin on the platelet surface before and after activation of 20mkM ADP. This analysis was performed on CytomicsFC500 flow cytometer using CD41/61-FITC and CD62P-PE mAB (Beckman Coulter, USA). The light transmission aggregatometry and VerifyNow (Accumetrics, USA) were chosen as a comparison method.
Results: In the female, compared with male, the platelet count was significantly higher: 246±12×109 cells vs 208±12×109 cells, respectively (p=0.02), but did not go beyond the accepted reference interval 150-400×109 cells. For male, the reference interval for the number of platelets expressing P-selectin on its surface reached 0.1-1.5%/cell and 9.7-42.7%/cell before and after ADP activation, respectively. And for female this reference interval was 0.2-4.1%/cell and 13.9-50.5%/cell before and after ADP activation, respectively. The cut-off value for effective DAT in PAD patients was the number of platelets expressing P-selectin below 12.0%/cell (sensitivity 96.6%, specificity 98.5%).
Conclusions: We determined the reference intervals for male and female, and set the cut-off value to assess the effectiveness of antiplatelet therapy. This study facilitates the transfer of platelet function testing by flow cytometry from a scientific instrument to a diagnostic test for use in clinical laboratories.
To cite this abstract in AMA style:Ermakov A, Gaykovaya L, Sirotkina O, Vavilova T. Analysis of Platelet Functional Activity by Flow Cytometry: Reference Intervals and Cut-off Value for Evaluating the Efficiency of Antiplatelet Therapy [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/analysis-of-platelet-functional-activity-by-flow-cytometry-reference-intervals-and-cut-off-value-for-evaluating-the-efficiency-of-antiplatelet-therapy/. Accessed November 26, 2020.
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