Coagulation laboratory tests
Factor XI assay

Topic Completed: 1 June 2012

Revised: 7 January 2019, last major update June 2012

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

PubMed Search: Factor XI assay [title]

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Cite this page: Parsons J. Factor XI assay. website. Accessed October 19th, 2019.
Definition / general
  • Determine by one step clotting activity assay, comparing dilutions of patient plasma to clotting times of dilutions of pooled plasma from normals
  • Use plasma from individuals with < 1% activity of immunodepleted normal plasma
  • Can also use chromogenic substrate after add inhibitors to factor XIIa and kallikrein
  • Levels may decrease during pregnancy
Additional references
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