VWFX - Overview: von Willebrand Factor Activity, Plasma

Test Catalog

Test Name

Test ID: VWFX    
von Willebrand Factor Activity, Plasma

Useful For Suggests clinical disorders or settings where the test may be helpful

Diagnosis of von Willebrand disease (VWD) and differentiation of VWD subtypes or differentiation of VWD from hemophilia A


Monitoring therapeutic efficacy of treatment with DDAVP (desmopressin) or VWF concentrates in patients with VWD

Reflex Tests Lists tests that may or may not be performed, at an additional charge, depending on the result and interpretation of the initial tests

Test IDReporting NameAvailable SeparatelyAlways Performed
RISTRistocetin Cofactor, PNoNo

Testing Algorithm Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

If von Willebrand factor activity is <55%, then the von Willebrand factor ristocetin cofactor activity assay will be performed at an additional charge.


MCF internal patients: von Willebrand factor activity results <55% will not reflex ristocetin cofactor unless ordered as part of von Willebrand profile. Recommend von Willebrand profile testing if not previously performed.

Special Instructions and Forms Library of PDFs including pertinent information and consent forms, specimen collection and preparation information, test algorithms, and other information pertinent to test

Method Name A short description of the method used to perform the test

Latex Particle Enhanced Immunoassay

NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.


Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name

von Willebrand Factor Activity, P

Aliases Lists additional common names for a test, as an aid in searching

Von Willeband factor activity
Ristocetin cofactor
VFW Activity