Ecarin clotting time

Ecarin clotting time (ECT) is a laboratory test used to monitor anticoagulation during treatment with hirudin, an anticoagulant medication which was originally isolated from leech saliva. Ecarin, the primary reagent in this assay, is derived from the venom of the saw-scaled viper, "Echis carinatus".

In the clinical assay, a known quantity of ecarin is added to the plasma of a patient treated with hirudin. Ecarin activates prothrombin through a specific proteolytic cleavage, which produces meizothrombin, a prothrombin-thrombin intermediate which retains the full molecular weight of prothrombin, but possesses a low level of procoagulant enzymatic activity. Crucially, this activity is inhibited by hirudin and other direct thrombin inhibitors, but not by heparin. The ECT is also unaffected by prior treatment with coumadin or the presence of phospholipid-dependent anticoagulants, such as lupus anticoagulant. Thus, the ECT is prolonged in a specific and linear fashion with increasing concentrations of hirudin. [cite journal |author=Nowak G |title=The ecarin clotting time, a universal method to quantify direct thrombin inhibitors |journal=Pathophysiol. Haemost. Thromb. |volume=33 |issue=4 |pages=173–83 |year=2003 |pmid=15583446 |doi=10.1159/000081505] Fabrizio MC. 2001. Use of Ecarin Clotting Time (ECT) with Lepirudin Therapy in Heparin-Induced Thrombocytopenia and Cardiopulmonary Bypass. JECT 33:117–125. [http://www.amsect.org/ce/HIT/ject_2001_v33_n2_fabrizio.pdf PDF] at [http://www.amsect.org/ Journal of The American Society of ExtraCorporeal Technology] . Accessed 5 June 2007.] [http://www.specialtylabs.com/books/display.asp?id=1060 Textarin/Ecarin Time] at [http://www.specialtylabs.com/ Specialty Laboratories] . Accessed 5 June 2007.]

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