Coagulation laboratory tests

Factor XI assay

Topic Completed: 1 June 2012

Minor changes: 21 September 2020

Copyright: 2002-2022,, Inc.

PubMed Search: Factor XI assay [title]

Jeremy C. Parsons, M.D.
Page views in 2021: 28
Cite this page: Parsons JC. Factor XI assay. website. Accessed January 17th, 2022.
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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