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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