Coagulation laboratory tests
Thrombin time

Topic Completed: 1 November 2012

Revised: 7 January 2019, last major update November 2012

Copyright: (c) 2002-2016,, Inc.

PubMed Search: Thrombin time [title]

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Definition / general
Cite this page: Parsons J. Thrombin time. website. Accessed June 7th, 2020.
Definition / general
  • Measures rate of fibrin clot formation after addition of standard concentration of thrombin to citrated plasma (Key, Makris, O'Shaughnessy and Lillicrap (Eds): Practical Hemostasis and Thrombosis, 2nd Edition, 2009 (Page 53))
  • Thrombin cleaves fibrinogen, releasing fibrinopeptides A and B, converting fibrinogen to fibrin
  • Useful to diagnose dysfibrinogenemia after more common disorders are excluded

  • Reference range: 10 - 13 or 16 - 24 seconds, depending on reaction conditions and thrombin concentration

  • Prolonged if even small amounts of heparin, hirudin or argatroban anticoagulants are present
  • Also prolonged with dysfibrinogenemia, amyloidosis (inhibits fibrinogen conversion to fibrin), DIC, thrombolytic therapy or thrombin inhibitors in patients exposed to bovine thrombin
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