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von Willebrand Factor Activity

Important Note

Orders placed for Ristocetin Cofactor will have a von Willebrand Factor Activity performed

Collection Requirements

Source: blood
Container: Sodium citrate light blue
Volume: 2.7 mL in vacutainer filled to the line

Turn Around Time

7 days

  • Batch testing completed on Fridays
  • Specimens must be received in Hematology by 9:00 a.m. to be included in the batch

Availability

Routine

Algorithm

This is a screening test. If the VWF ACT is ≤55% and/or the VWF ACT/VWAg ratio is <0.70, the specimen will be sent to Versiti Wisconsin for VWF Glycoprotein IbM Activity.

Lab Processing Instructions

Specimen: plasma
Double spin, aliquot into 2 tubes
Freeze if testing will not be completed within 1 hour of processing

 

Offsites:

  • STAT: Send plasma at room temperature with a STAT courier
  • Routine: Send plasma on dry ice

Performing Laboratory

Adele Hall

Adele Hall Lab Section

Hematology

Instrumentation/Methodology

Stago STAR

Reference Ranges

50-150%