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Clinical use of coagulation tests

James L Zehnder, MD
Section Editor
Lawrence LK Leung, MD
Deputy Editor
Jennifer S Tirnauer, MD


Several tests of the coagulation system are available, including the prothrombin time (PT), activated partial thromboplastin time (aPTT), and others; these may be ordered in a variety of clinical settings. This topic reviews the principles and interpretation of coagulation tests that are routinely available for clinical use.

Additional information regarding the use of these tests in specific clinical settings is presented separately:

Unexplained bleeding – (See "Approach to the adult patient with a bleeding diathesis" and "Approach to the child with bleeding symptoms".)

Preoperative testing – (See "Preoperative assessment of hemostasis".)

Monitoring anticoagulation:


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Literature review current through: Sep 2015. | This topic last updated: Sep 28, 2015.
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