Some von Willebrand questions from “Charlie” in Edmonton:
What are the reference ranges for von Willebrand factor (VWF) antigen and for factor VIII? And what might cause these values to increase in a person who was originally thought to have a problem with being able to clot?
Hi, Charlie. the typical reference ranges for VWF assays are:
VWF activity (ristocetin cofactor): 50–166%
VWF antigen (immunoassay): 50–249%
Coagulation factor VIII activity (clot-based): 50–186%
These are taken from Marques MB, Fritsma GA. Quick Guide to Coagulation Testing, 2nd Edition, 2009, AACC Press, and will vary slightly by locale and institution. Your local laboratory manual should provide the ranges for your institution.
VWF and factor VIII levels are acute phase proteins and rise in response to inflammation. Often women with mild type 1 von Willebrand disease, for instance, will see their mucocutaneous bleeding symptoms disappear during pregnancy, yet return post-partum. Most people with mild or moderate von Willebrand disease see their symptoms rise and fall over the course of months or years. Geo.