Physiology In healthy subjects, there is a dynamic equilibrium between coagulation and platelets forming a hemostatic plug to close the wound and the fibrinolytic system removing fibrin to prevent vascular occlusion. Fibrinolysis is initiated by the formation of fibrin. Tissue…
FXIII is a hemostatic protein that plays a critical role in stabilizing fibrin networks at the site of injury and thus preventing premature fibrinolysis. In the plasma, FXIII circulates as a tetrameric zymogen composed of two catalytic alpha chains (FXIII-A)…
Antiplatelet medications are widely used to treat or prevent thrombosis in a variety of cardiovascular disorders. Currently available antiplatelet drugs comprise four categories: 1. Acetylsalicylic acid (aspirin) inhibits cyclooxygenase (COX-1), 2. P2Y12 receptor antagonists (clopidogrel, ticlopidine, prasugrel, cangrelor, ticagrelor) block…
Laboratory investigation of a suspected inherited platelet disorder (IPD) requires both standard and confirmatory platelet laboratory testing. The former includes platelet count, mean platelet volume and other indices by a hematology analyzer, peripheral blood smear review by light microscopy, and…
Platelet function defects (PFD) should be considered in patients with symptoms suggestive of a defect in primary hemostasis. A genetic disorder may be present, particularly if symptoms are lifelong or familial; however, most PFD encountered in clinical practice are acquired.…
The platelet is a dynamic structure, covered externally with glycoprotein (GP) receptors. Internally, the platelet possesses alpha (α) granules, which contain a number of proteins, including von Willebrand factor (VWF), fibronectin, and fibrinogen; and dense (δ) granules, containing adenosine triphosphate…
Recent years have seen a significant increase in the utilization of rotational viscoelectric global hemostasis testing in point-of-care settings in support of complicated surgical procedures and trauma. The current instruments allow near real-time data gathering, with many results being available…
The platelet function analyzer (PFA)-100 is the most widely used global test of primary hemostasis. It performs an in vitro test of platelet plug formation, referred to as the PFA, by measuring the time to occlusion of a window in a…
Numerical platelet determination is a critical step in assessing bleeding and thrombosis risk. Additionally, platelet count serves as a biomarker for a number of pathologic states. Modern automated hematology analyzers produce fast, accurate, and precise platelet determination under most circumstances.…
von Willebrand disease (VWD) may be treated by 1) raising the patient’s own von Willebrand factor (VWF), 2) replacement of VWF, or 3) use of adjuvant therapies with a global effect on hemostasis. A treatment plan must be based on…