Abstract Number: PB0897
Meeting: ISTH 2021 Congress
Background: Modified Ivy’s Bleeding time(BT) is low cost but skill-based, invasive and operator-dependent screening test for platelet function defects(PFD). Platelet Function Analyzer-200 (PFA-200) is a pseudo-physiological system wherein citrated whole blood is drawn at high shear through a small aperture in membrane coated with collagen/epinephrine or collagen/ADP, causing platelet adhesion and aggregation occluding the aperture. Time from the start of the test until occlusion of the aperture is the Closure Time(CT). Prolonged CT indicates primary haemostatic defect.
Aims: To assess the performance of modified Ivy’s BT and PFA-200 CT as screening tests for PFD.
Methods: Patients referred to our institution for bleeding workup from January 2016-January 2021 were included after informed consent. Detailed workup was done by complete blood count, BT, PFA-200 CT using Collagen/ADP and Collagen/Epinephrine cartridges, light transmission aggregometry, lumi-aggregometry, flow cytometry, mepacrine uptake/release assay, Prothrombin time, Activated partial thromboplastic time, Fibrinogen, Factor Assays and Ristocetin Cofactor assay. Patients with coagulation factor deficiency or Von Willebrand Disease were excluded. Patients with PFD were included, while patients with no haemostatic defect after detailed workup(n=120) were taken as controls.
Results: Total of 498 patients were included out of which 67 had Bernard Soulier Syndrome(BSS), 208 had Glanzmann Thrombasthenia(GT),103 had mild PFD(storage pool defect / signal transduction defect / secretion defect) and 120 patients with no haemostatic defect were taken as controls. Overall, CT on PFA-200 Collagen/Epinephrine had highest sensitivity(98.6%) and negative predictive value(NPV)(96%) as screening tool for PFD. Sensitivity and NPV of BT, PFA-200 using Collagen/ADP and Collagen/Epinephrine was maximum(100%) for identification of GT followed by BSS and least for mild PFDs.(Figure1,2)
Conclusions: Sensitivity and NPV for BT, PFA-200 CT for Collagen/Epinephrine as well Collagen/ADP were comparable for identification of severe platelet function defects (GT,BSS), but CT on Collagen/Epinephrine had maximum sensitivity and NPV as a screening tool for identification of mild PFD.
To cite this abstract in AMA style:Dave R, Geevar T, Mammen J, Chellaiya G, Samuel A, Vijayan R, Singh S, Nair S. Utility of Modified Ivy’s Bleeding Time and Closure Time on Platelet Function Analyzer-200 as a Screening Tool to Identify Platelet Function Disorders [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/utility-of-modified-ivys-bleeding-time-and-closure-time-on-platelet-function-analyzer-200-as-a-screening-tool-to-identify-platelet-function-disorders/. Accessed August 9, 2022.
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