The most common use of snake venom molecules as reagents in hemostasis is described below. Fibrinogen Assessment Fibrinogen promotes platelet aggregation and is converted to fibrin by thrombin, with formation of a hemostatic plug. Reptilase Time This is a modification…
The TGA is a global test of coagulation systems, with the potential to contribute to the current arsenal of clinical prognostication and drug monitoring tools. By varying the conditions under which it is applied, the test can be made sensitive…
Microparticle (MP) analysis has become popular in the last decade because of mounting evidence of their active role in multiple cellular processes. Alterations in total MP numbers or changes in the relative abundance of MP populations have been correlated with…
Laboratory testing modalities and recommendations for monitoring heparin, heparin-like medications, direct thrombin inhibitors (DTIs), and direct anti-Xa inhibitors (DXIs), including indications, testing recommendations, testing modalities, and test limitations are discussed below. There are several options available for laboratory monitoring of…
Classic Acquired Prothrombotic Conditions Although there is a growing number of known established thrombophilias with an underlying genetic basis, the majority of venous thromboembolism events are provoked in the context of an acquired hypercoagulability state, leading to venous thrombosis. These…
Protein S (PS) is a vitamin K–dependent plasma glycoprotein that serves as a cofactor of activated protein C (APC). When bound to APC, it accelerates protein C–dependent degradation of factor (F) Va and FVIIIa. PS deficiency is inherited in an…
Protein C (PC) is a vitamin K–dependent, heterodimeric, plasma glycoprotein that is synthesized as a zymogen in the liver. It is activated on the endothelial surface by the thrombin–thrombomodulin (TM) complex. Once produced, the activated protein C (APC) cleaves and…
Congenital antithrombin (AT) deficiency occurs in 0.2%–0.02% of the general population. However, in patients who had suffered a venous thromboembolic event (VTE), the prevalence is approximately 1%–3%. Preanalytical variables must be taken into account when deciding on the timing of…
Abnormal thrombosis is a result of a pathologic shift in the balance between antihemorrhagic (prothrombotic) and antithrombotic factors toward conditions that favor thrombus formation at the wrong time and/or in the wrong location. The Virchow triad of blood stasis, inflammation,…
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)…