vWF Activity
Alternate Names
164509 LC, Ristocetin Cofactor
SoftLab Order Code
VWFA
Epic Order Name
VON WILLEBRAND FACTOR (VWF) ACTIVITY, REF LAB LC 164509
Epic Order ID
LAB331
Tests Included
Quantitative platelet agglutination with ristocetin
Laboratory
Reference Lab
Sample Type
Plasma
Collection Container
Blue Top (Sodium Citrate - Light blue)
Collecting Volume
One full light blue top tube
Minimum Collecting Volume
One full light blue top tube
Storage or Stability
Frozen
Causes for Rejection
Gross hemolysis; clotted specimen; frozen specimen thawed in transit
Patient Preparation
Avoid warfarin (Coumadin(R)) therapy for two weeks and heparin therapy for two days prior to the test. Do NOT draw from an arm with a heparin lock or heparinized catheter.
Instructions
If the patient's hematocrit exceeds 55%, the volume of citrate in the collection tube must be adjusted.