Q: What is Ecarin clotting time (ECT)?

Answer:  Clinically not in much use but "Ecarin Clottting Time" is the most precise way to measure/monitor the activity of Direct Thrombin Inhibitors (DTIs). Though most of the literature is available with experience to hirudin, but is likely to be useful to other DTIs, in particular to new oral direct thrombin inhibitors.

Ecarin, the primary reagent in this assay, is derived from the venom of the saw-scaled viper, Echis carinatus.

This is an important test to be aware of in ICU as both Activated Clotting Time (ACT) and PTT have no particular linear correlation between the plasma DTIs levels and their activities particularly at higher level.

Refer to lab. for reference therapeutic level for a particular DTI.

References:

1. Di Nisio M, Middeldorp S, Büller H (2005). "Direct thrombin inhibitors.". N Engl J Med 353 (10): 1028–40

2.  Use of Ecarin Clotting Time (ECT) with Lepirudin Therapy in Heparin-Induced Thrombocytopenia and Cardiopulmonary Bypass. JECT 33:117–125.

3.  Lange U, Nowak G, Bucha E. Ecarin chromogenic assay—a new method for quantitative determination of direct thrombin inhibitors like hirudin. Pathophysiol Haemost Thromb. 2003 Jul-2004 Aug;33(4):184-91.

4. Pathophysiol. Haemost. Thromb. 33 (4): 173–83.