Laboratory Medicine
Test Directory / vWF Activity Assay
vWF Activity Assay
Citrate Plasma
| Test | vWF Activity Assay |
|---|---|
| Common Abbreviations | vWF:GP1b or vWF:Act |
| Profile | von Willebrand's Disease Screen: vWF:Activity (vWF:GP1b) vWF:Antigen (vWF:Ag) vWF:Collagen Binding Assay (vWF:CB) Factor VIII Assay Coagulation Screen |
| Clinical Indication | vWF: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 Type | Blood |
| Sample Type | Citrate Plasma |
| Minimum Volume | total required for a vWD Screen: 3 x 3mL (adult) 3 x 1mL (paed) (citrated plasma must be filled to bottle line) |
| Special Precautions | Must state if patient is on anticoagulants (DOAC, Warfarin, Heparin); known coagulation disorders; clincal symptoms (bleeding, bruising). |
| Stability | 4-6 hours |
| Turnaround Time | 4 hours (urgent) 3 weeks (routine) |
| Laboratory | York Hospital |
| Reference Interval | Reference range printed on final report. |
| Limitations | Haemolysis, 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 |
