Coagulation
Coagulation laboratory tests
Factor VIII assay



Topic Completed: 1 June 2012

Revised: 7 January 2019, last major update June 2012

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PubMed Search: Factor VIII assay [title]


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Cite this page: Parsons J. Factor VIII assay. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/coagulationfactorVIII.html. Accessed December 6th, 2019.
Definition / general
  • Assay is usually a PTT - based clotting assay that measures factor VIII activity
  • Use severely deficient factor VIII plasma as substrate for one stage clotting assay, although there is tremendous interlaboratory variability
  • Can also use chromogenic assay, particularly when assessing B - chain deleted recombinant Factor VIII (i.e. “Refacto”)

  • Low levels:
    • Hemophilia, vWF disease with decreased vWF antigen levels, delay in transporting specimen to lab

  • Note:
    • Levels are not greatly decreased at birth or throughout childhood
    • Levels may increase during pregnancy

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