Coagulation laboratory tests
Factor XI assay

Author: Jeremy Parsons, M.D. (see Authors page)

Revised: 13 May 2016, last major update June 2012

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

PubMed Search: Factor XI assay [title]

Cite this page: Factor XI assay. website. Accessed October 18th, 2018.
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