Cite this page: Parsons J. Factor XI assay. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/coagulationfactorXI.html. Accessed December 5th, 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