von Willebrand Factor Antigen
Test Code
Clinical Significance
von Willebrand Factor Antigen - von Willebrand Disease is the most common hereditary bleeding disorder; it may also be acquired. von Willebrand Factor is necessary for platelet adhesion to injured endothelium. von Willebrand Factor Antigen is useful in assessing the quantity of von Willebrand Factor. When combined with other tests, results are useful in categorizing the type of von Willebrand Disease.
Test Resources
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Test Details
Preferred Specimen(s)
1 mL frozen platelet-poor plasma collected in 3.2% sodium citrate (light blue-top) tube
Minimum Volume
0.5 mL
Collection Instructions
Platelet-poor plasma: Centrifuge light blue-top tube for 15 minutes at approximately 1500 g within 60 minutes of collection. Using a plastic pipette, remove plasma, taking care to avoid the WBC/platelet buffy layer and place into a plastic vial. Centrifuge a second time and transfer platelet-poor plasma into a new plastic vial. Plasma must be free of platelets (<10,000/uL). Freeze immediately and ship on dry ice.
Note: Storage of whole blood at refrigerated temperatures prior to processing may lead to cryoprecipitate formation and falsely low Factor VIII and von Willebrand Factor studies.
Transport Container
Transport tube
Transport Temperature
Frozen
Specimen Stability
- Room temperature: Unacceptable
- Refrigerated: Unacceptable
- Frozen: 30 days
Reject Criteria
Hemolysis • Received room temperature • Received refrigerated
Setup Schedule
Note: Storage of whole blood at refrigerated temperatures prior to processing may lead to cryoprecipitate formation and falsely low Factor VIII and von Willebrand Factor studies.
Refrigerated: Unacceptable
Frozen: 30 days