What is the role of the vWF antigen (vWF:Ag) assay in the diagnosis of von Willebrand disease (vWD)?

Updated: Dec 30, 2019
  • Author: Eleanor S Pollak, MD; Chief Editor: Srikanth Nagalla, MBBS, MS, FACP  more...
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Answer

This assay is usually performed (with rabbit antibody to vWF) using either a quantitative immunoassay or an enzyme-linked immunosorbent assay. A discrepancy between the vWF:Ag value and RCoF activity suggests a qualitative defect that should be further investigated by characterization of the vWF multimeric distribution. As with RCoF, a vWF:Ag level below 30 IU/dL is considered diagnostic of vWD, but levels of 30-50 IU/dL may be found in some patients with type 1 or 2 vWD. [13]


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