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Epic Code LAB1230904 von Willebrand Factor Activity (VWF Activity)

Important Note

There is currently a nationwide shortage of this tube. Please take steps to ensure specimen integrity to reduce recollection. Specimen Tube Shortage (link)

Test Name Alias

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

Interface Order Alias


Clinical Information

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. 

Collection Instructions

Specimen Collection: Blood


Container(s): 3.2% Na Citrate Tube (blue top)

Preferred Volume to Collect: 2.7 mL (full tube)

Minimum Volume to Collect: 1.8 mL (full tube)

Capillary collect ok: No

Microtainer acceptable: No


Collection Instructions:



Processing Instructions (Laboratory, Outpatient or Off-site collection)


Processed Specimen: Platelet Poor Plasma

Centrifuge/Spin: Yes

Aliquot: Yes

Processing Instructions:

  • Detailed instructions (link): Preparing Platelet Poor Plasma
  • Separate plasma into 2 – 3 aliquots, minimum of 0.5 mL each.
  • Freeze aliquots in plastic transport tubes immediately.

Transport Temperature:

  • Ambient (up to 1 hour in whole blood state)
  • Frozen (plasma only >1 hour)

Rejection Criteria

Specimen has been thawed

Specimen Stability

Ambient: 1 hour

Frozen: 2 months

Laboratory Retention: 2 months

Test Frequency

Available Monday-Friday, usual TAT 1-4 days.

Reference Range

50-200 %

Performing Department


Performing Department Laboratory Location

Corewell Health Reference Laboratory, Grand Rapids, MI


von Willebrand factor GP1bM-binding activity



CDM Code


Epic Test ID



currently unavailable

Mayo Access Code

currently unavailable

Reviewed Date


Last Updated Date