Reptilase time (RT) is a

blood test A blood test is a laboratory analysis performed on a blood sample that is usually extracted from a vein in the arm using a hypodermic needle, or via fingerprick. Multiple tests for specific blood components, such as a glucose test or a ch ...

used to detect deficiency or abnormalities in

fibrinogen Fibrinogen (factor I) is a glycoprotein complex, produced in the liver, that circulates in the blood of all vertebrates. During tissue and vascular injury, it is converted enzymatically by thrombin to fibrin and then to a fibrin-based blood ...

, especially in cases of

heparin Heparin, also known as unfractionated heparin (UFH), is a medication and naturally occurring glycosaminoglycan. Since heparins depend on the activity of antithrombin, they are considered anticoagulants. Specifically it is also used in the trea ...

contamination.

Reptilase Batroxobin, also known as reptilase, is a snake venom enzyme with Venombin A activity produced by ''Bothrops atrox'' and ''Bothrops moojeni'', venomous species of pit viper found east of the Andes in South America. It is a hemotoxin which acts as ...

, an enzyme found in the

venom Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a ...

of Bothrops snakes, has activity similar to

thrombin Thrombin (, ''fibrinogenase'', ''thrombase'', ''thrombofort'', ''topical'', ''thrombin-C'', ''tropostasin'', ''activated blood-coagulation factor II'', ''blood-coagulation factor IIa'', ''factor IIa'', ''E thrombin'', ''beta-thrombin'', ''gamma- ...

. Unlike thrombin, reptilase is resistant to inhibition by

antithrombin III Antithrombin (AT) is a small glycoprotein that inactivates several enzymes of the coagulation system. It is a 432-amino-acid protein produced by the liver. It contains three disulfide bonds and a total of four possible glycosylation sites. α-Ant ...

. Thus, the reptilase time is not prolonged in blood samples containing heparin,

hirudin Hirudin is a naturally occurring peptide in the salivary glands of blood-sucking leeches (such as '' Hirudo medicinalis'') that has a blood anticoagulant property. This is fundamental for the leeches’ habit of feeding on blood, since it keeps a ...

, or direct thrombin inhibitors, whereas the thrombin time will be prolonged in these samples. Reptilase also differs from thrombin by releasing

fibrinopeptide A The fibrinopeptides, fibrinopeptide A (FpA) and fibrinopeptide B (FpB), are peptides which are located in the central region of the fibrous glycoprotein fibrinogen (factor I) and are cleaved by the enzyme thrombin (factor IIa) to convert f ...

, but not fibrinopeptide B, in its cleavage of

References

Blood tests {{pathology-stub