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Coagulation laboratory tests

Factor VIII assay

Reviewer: Jeremy Parsons, M.D. (see Reviewers page)
Revised: 21 June 2012, last major update June 2012
Copyright: (c) 2002-2012, PathologyOutlines.com, Inc.


● 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

● Levels are not greatly decreased at birth or throughout childhood
● Levels may increase during pregnancy

Additional references

Kessler, C. (2007). Hemorrhagic disorders: Coagulation factor deficiencies. In L. Goldman, D. Ausiello (Eds.), Cecil Medicine (pp.1301-1313). Philadelphia, PA: Saunders Elsevier.

End of Coagulation > Coagulation laboratory tests > Factor VIII assay

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