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von Willebrand Factor Antigen
Test Code10148
CPT Codes
85246<br /> Limited Access Code
Preferred Specimen
1 mL frozen citrated plasma collected from 3.2% sodium citrate (light blue-top) tube
Minimum Volume
0.5 mL
Instructions
Please submit a separate, frozen vial for each special coagulation assay ordered.
Platelet-Poor Plasma: Centrifuge light blue-top tube for 15 minutes at approximately 1500 x g within 60 minutes of collection. Using a plastic pipette, remove plasma, taking care to avoid WBS/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/mcL). Freeze immediately and ship on dry ice.
Note: Storage of whole blood at refrigerated temperature before processing may lead to cryoprecipitate formation and falsely low Factor VIII and von Willebrand Factor studies.
Platelet-Poor Plasma: Centrifuge light blue-top tube for 15 minutes at approximately 1500 x g within 60 minutes of collection. Using a plastic pipette, remove plasma, taking care to avoid WBS/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/mcL). Freeze immediately and ship on dry ice.
Note: Storage of whole blood at refrigerated temperature before processing may lead to cryoprecipitate formation and falsely low Factor VIII and von Willebrand Factor studies.
Transport Temperature
Frozen
Specimen Stability
Room temperature: 8 hours
Refrigerated: 24 hours
Frozen: 30 days
Refrigerated: 24 hours
Frozen: 30 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Hemolyzed specimens
Methodology
Immunoturbidimetric
Setup Schedule
Set up: Mon-Fri; Report available: Next day
Reference Range
50-217%
Clinical Significance
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.
