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Von Willebrand Factor (VWF) Antigen


TEST DIRECTORY
Test Name
Von Willebrand Factor (VWF) Antigen
Test Code
VWF_AG
SPECIMEN REQUIREMENTS
Specimen Requirements
Minimum of 4.0 mL frozen plasma, with 1.0 mL in each aliquot, for a total of 4 aliquots.
Supplies for Submission
Light Blue Top (5)
Specimen Collection

Patient should abstain from oral anticoagulant therapy (upon the advice of physician) for at least 2 weeks before collecting sample.

  1. Fill up each Light Blue Top tube as completely as possible and mix by gently inverting the tube 5-6 times.
    Inadequate filling will distort the exact ratio of 1 part sodium citrate to 9 parts blood required for accurate results.
  2. Immediately centrifuge the specimen at 1500 RCF for 15 minutes.
  3. Pipette the supernatant plasma and transfer to a plastic transport tube.
  4. Re-centrifuge plasma in the transport tube at 1500 RCF for 15 minutes to make sure that no red blood cells are present.
  5. Pipette the top two-thirds of the supernatant plasma and transfer ≥1.0 mL to a second transport tube (submit 4 tubes total), labeled with two patient identifiers.
  6. Label aliquot tube as citrate plasma and immediately freeze at -20 °C or lower for transport.
Storage Requirements
Critical Frozen (CFZ)
GENERAL AND TECHNICAL INFORMATION
Turn Around Time
12 days
CPT Code
85246