Von Willebrand's Screen

Message
If unable to process and properly store specimens within 4 hours of collection then call CompuNet transportation for a STAT pick-up at (937) 297-8262 option 1.  

This test needs a completed Anticoagulant Drug List submitted with the specimen. For a copy of the 2 page form
click here
 

Test Code
91146

CPT Codes
85240;85244;85245

Includes
Von Willebrand's Activity(70592)
Von Willebrand's Antigen(70587)
Factor VIII Assay(70595)

Preferred Specimen
3 plastic (2.7mL) completely filled Sodium Citrate (light blue top) tube

Minimum Volume
3 Frozen Capped aliquots of Sodium Citrate plasma (Polypropylene tubes recommended)

Instructions
Use standard venipuncture and disposal techniques.
Collect the required quantity of Sodium Citrate (light blue top) tubes.

If unable to process specimens within 4 hours of collection then call CompuNet transportation for a STAT pick-up at (937) 297-8262 option 1.

Sodium Citrate (light blue top) tube(s): Process immediately (stable only 4 hours), following instructions below:
Note: We recommend aliquot tubes to be made of polypropylene plastic as this material is safe to freeze at <-70 degrees C.
1. Centrifuge capped Sodium Citrate (light blue top) tubes at 3000 rpm for 10 minutes, or at speed and time required to consistently produce Platelet Poor Plasma (<5/kmm3).
2. Carefully remove the plasma from all Sodium Citrate (light blue top) tubes; avoid disturbing the WBC/buffy coat, and combine all plasma into a 15mL plastic conical centrifuge tube.
Note: If the plasma shows any hemolysis, it must be recollected.
3. Centrifuge the plasma in the 15mL plastic conical centrifuge tube for a second time as in step 1.
4. In one smooth motion, carefully and quickly pour the centrifuged plasma into a second 15mL plastic conical centrifuge tube. A small amount of plasma along with a red cell button should remain on the bottom of the original conical tube if the pour was executed correctly. Note: This quick-pour method prevents platelet transfer and contamination.
5. Aliquot at least 1mL of plasma into each aliquot tubes labeled “plasma.” Refer to the Minimum Volume section above for the number of aliquots required per test.
6. Finally, place all aliquots into a <-20°C freezer within 4 hours.
Note: Aliquots must remain frozen until they are picked up by the CompuNet courier. Call CompuNet transportation department if frozen specimen boxes are needed.

Transport Container
Whole blood Sodium Citrate (light blue top) tube
    OR
Frozen
-Capped aliquots of Sodium Citrate plasma (Polypropylene tubes recommended)

Transport Temperature
Room Temperature: Whole blood Sodium Citrate (light blue top) tube
Refrigerated: Unacceptable for Sodium Citrate (light blue top) tube whole blood or capped plasma aliquots
Frozen: Capped aliquots of Sodium Citrate plasma (Polypropylene tubes recommended)

Specimen Stability
Room Temperature: Whole blood Sodium Citrate (light blue top) tube < 4 hours
Refrigerated: Unacceptable for Sodium Citrate (light blue top) tube whole blood or capped plasma aliquots
Frozen: Capped aliquots of Sodium Citrate plasma (Polypropylene tubes recommended) <6 months at ≤-70 degrees C

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Rejected for hemolysis, clotted, improper fill, incorrect specimen type, thawed frozen aliquots, refrigerated plasma or blood, expired test tubes, >4 hours old if not processed into separated frozen plasma vials.

Methodology
Clotting, ELISA

Setup Schedule
Tuesday and Friday
SCOAG

Report Available
1 - 3 days

Limitations
Results may vary during pregnancy

Clinical Significance
Von Willebrand’s Factor is part of the Factor VIII complex. It functions as the carrier for Factor VIII in circulation. Normal to decreased levels of Von Willebrand’s Factor may be found in Von Willebrand’s disease. Normal to increased levels are found in hemophilia, inflammatory responses and last trimester of pregnancy. An alternative methods for testing for Von Willebrand’s antigen is immunoelectrophoresis and Von Willebrand’s activity is platelet aggregometry.

Performing Laboratory
CompuNet Clinical Laboratories, LLC
2308 Sandridge Drive
Moraine, OH 45439



The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.