Abstract
Snake venoms have evolved primarily to immobilize and kill prey, and consequently,
they contain some of the most potent natural toxins. Part of that armory is a range
of hemotoxic components that affect every area of hemostasis, which we have harnessed
to great effect in the study and diagnosis of hemostatic disorders. The most widely
used are those that affect coagulation, such as thrombin-like enzymes unaffected by
heparin and direct thrombin inhibitors, which can help confirm or dispute their presence
in plasma. The liquid gold of coagulation activators is Russell's viper venom, since
it contains activators of factor X and factor V. It is used in a range of clotting-based
assays, such as assessment of factor X and factor V deficiencies, protein C and protein
S deficiencies, activated protein C resistance, and probably the most important test
for lupus anticoagulants, the dilute Russell's viper venom time. Activators of prothrombin,
such as oscutarin C from Coastal Taipan venom and ecarin from saw-scaled viper venom,
are employed in prothrombin activity assays and lupus anticoagulant detection, and
ecarin has a valuable role in quantitative assays of direct thrombin inhibitors. Snake
venoms affecting primary hemostasis include botrocetin from the jararaca, which can
be used to assay von Willebrand factor activity, and convulxin from the cascavel,
which can be used to detect deficiency of the platelet collagen receptor, glycoprotein
VI. This article takes the reader to every area of the diagnostic hemostasis laboratory
to appreciate the myriad applications of snake venoms available in diagnostic practice.
Keywords
coagulation assays - hemostasis - Russell's viper venom - snake venom toxins - snake
venom thrombin-like enzymes
