Coagulation laboratory tests
Ecarin clotting time

Topic Completed: 1 June 2012

Revised: 7 January 2019, last major update June 2012

Copyright: (c) 2002-2012,, Inc.

PubMed Search: Ecarin clotting time

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Definition / general
Cite this page: Parsons J. Ecarin clotting time. website. Accessed August 8th, 2020.
Definition / general
  • Measures activity of hirudin in plasma, important since severe bleeding can occur with hirudin overdose and no antidote is known
  • Also measures activity of lepirudin, a recombinant form of hirudin (J Extra Corpor Technol 2001;33:117)
  • Ecarin catalyzes prothrombin to meizothrombin, an active form that is inhibited by hirudin (Pathophysiol Haemost Thromb 2004;33:173)
  • Test measures ability of hirudin to complex with / inhibit meizothrombin as ecarin produces it from prothrombin
  • Ecarin comes from the venon of the saw - scaled viper

  • Specimen:
    • Sodium citrate tube filled to top
    • Freeze immediately until testing occurs
    • Specimens with clots or hemolysis are unacceptable, unless hemolysis is due to cardiopulmonary bypass and is produced in vivo
    • Do not draw from heparinized catheter

  • Reference range:
    • 22.6 to 29.0 seconds
    • Prolonged if hirudin or argatroban (direct thrombin inhibitors) present; also hypofibrinogenemia, dysfibrinogenemia
    • False positive if prothrombin deficiency is present

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