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Laboratory Medicine

Test Directory / vWF Activity Assay

vWF Activity Assay

Citrate Plasma

TestvWF Activity Assay
Common AbbreviationsvWF:GP1b or vWF:Act
Profilevon Willebrand's Disease Screen: vWF:Activity (vWF:GP1b) vWF:Antigen (vWF:Ag) vWF:Collagen Binding Assay (vWF:CB) Factor VIII Assay Coagulation Screen
Clinical IndicationvWF:Act is used to assess if the vWF is functioning properly against platelets. Von Willebrand factor (VWF) testing is used to investigate excessive or recurrent bleeding episodes or a personal or family history of excessive bleeding. Testing is used to help diagnose von Willebrand disease (VWD) and distinguish between the various types of VWD. Always used in as part of a vWD Screen
Specimen TypeBlood
Sample TypeCitrate Plasma
Minimum Volumetotal required for a vWD Screen: 3 x 3mL (adult) 3 x 1mL (paed) (citrated plasma must be filled to bottle line)
Special PrecautionsMust state if patient is on anticoagulants (DOAC, Warfarin, Heparin); known coagulation disorders; clincal symptoms (bleeding, bruising).
Stability4-6 hours
Turnaround Time4 hours (urgent) 3 weeks (routine)
LaboratoryYork Hospital
Reference IntervalReference range printed on final report.
LimitationsHaemolysis, gross lipaemia, high haematocrit may interfere with measurement. Over or under filled samples cannot be used due to ratio between blood and citrate
Additional Information
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