von Willebrand Factor Activity (VWF Activity)

von Willebrand Factor Activity (VWF Activity)

Alternate Test Name

VWF GPIbM Activity, GP1B, Ristocetin cofactor, VWF Activity, Von Willebrand Factor Activity

Epic Mnemonic
Sunquest Mnemonic

LAB115441
VWF

Category

Sendouts

Methodology

von Willebrand factor GP1bM-binding activity

Test Performance Schedule

Monday - Friday

Result Availability

1 – 4 days

Container

Light blue top tube (3.2% buffered sodium citrate)

Volume

Pref. Vol.: 2.7 mL (2-3 aliquots, minimum of 0.5 ml each)
Min. Vol.: 1.8 mL (2-3 aliquots, minimum of 0.5 ml each)

Collection Instructions

• Routine venipuncture
•Immediately after collection, gently invert tube 5-10 times
• Specimen must be processed within 1 hour of collection
•Platelet-poor plasma:  Centrifuge light-blue top for 15 minutes at approximately 1500 g within 1 hour of collection.  Using a plastic pipette, remove plasma, taking care to avoid the WBC/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).
• Separate plasma into2-3 aliquots, minimum of 0.5 mL each
•Freeze immediately

Transportation Instructions

Frozen

Stability

• Room Temperature: 1 hour (whole blood)
• Refrigerated: Not Acceptable
• Frozen: 2 months (plasma only)

Causes for Rejection

Frozen whole blood, thawed plasma specimen

CPT Codes

85397

Effective/Revised

1/13/23

Diagnostic automated assay for the quantitative determination of the von Willebrand factor GP1b-binding activity. Utilized for the evaluation of congenital and acquired von Willebrand syndrome