Test Code VWFAG VON WILLEBRAND FACTOR ANTIGEN, PLASMA
Performing Laboratory
NorDx Laboratories
Useful For
Diagnosing von Willebrand’s disease when used in conjunction with “Factor VIII Assay”, “Von Willebrand Factor Assay (Ristocetin CoFactor)”, and “Platelet Aggregation With Ristocetin” assay
Method Name
Latex Immunoturbidometric Assay
Reference Values
50-160 %
Days and Times Test Performed
Monday
Report Available
1 Day
Specimen Type
Plasma
Preferred Container
Light Blue Top Tube (Sodium Citrate) – Tube must be full at time of collection.
Specimen Collection and Handling
Collect specimen as follows:
1. Draw blood light blue-top (3.2% sodium citrate) tube(s). Tube(s) must be full upon collection.
2. Separate plasma from cells within 4 hours of collection in a centrifuge at 2,500 rpm for 15 minutes or 3,000 rpm for 10 minutes.
3. Using a plastic transfer pipette (do not use a glass pipette) decant the plasma to a screw-capped, plastic (polypropylene) vial. Glass vials will not be accepted.
4. Spin the plasma again at 2,500 rpm for 15 minutes or 3,000 rpm for 10 minutes.
Note: Double spinning the specimen ensures platelet poor plasma (<10,000 uL)
5. Divide the plasma into as many 0.5-1.0 mL aliquots as possible and cap the vial(s) tightly.
6. Place tubes upright and freeze specimen(s) immediately at ≤ – 20º C.
7. Send specimen(s) FROZEN on dry ice.
Click here to view the Procedure for Collecting a Specimen from an A-line
Specimen Stability Information
Specimen Type: Plasma
Room Temp: 4 Hours
Note: Whole blood that remains capped and unspun is stable for up to 4 hours when stored at room temperature (18 – 24°C). Frozen plasma is stable 2 weeks @ -20°C and 12 months @ -70°C. Blue top tubes for coag assays must not be refrigerated or placed on ice.
Add On Capable
Yes
Advance Beneficiary Notice Requirements
No ABN Required
CPT Code Information
CPT Code |
CPT Description |
CPT Disclaimer |
---|---|---|
85246 | Clotting, Factor VIII von Willebrand (VW), Factor Antigen |
Performing Laboratory Location
NorDx Laboratories
LOINC Code Information
27816-8
Keywords
VON WILLEBRAND FACTOR
Rejection Information
Underfilled (< 90%), clotted, high hematocrit (> 55%), or grossly hemolyzed