This test aids to diagnosis of congenital or acquired vWF deficiencies in patients with bleeding disorders or at risk for vWF deficiency. The VWF plays an important role both in primary hemostasis by the formation of the hemostatic plug, due to its function in platelet adhesion and aggregation, and in the coagulation process by the stabilization of FVIII. Von Willebrand Disease (VWD) is the most common inherited bleeding disorder. Clinically, it is often characterized by muco-cutaneous hemorrhages.
The 9:1 blood/citrate ratio must be kept constant. Adjustments for the amount of anticoagulant should be made when the hematocrit is abnormal (above 55%). Mix immediately to prevent clotting.
Collection Instructions
Send whole blood sample(s) at room temperature as soon as possible. If specimens cannot be shipped immediately, centrifuge and separate plasma within 1 hour of collection, send frozen plasma on dry ice
8 hrs at Room Temperature, 12 months at -70ºC or below.
vWF Antigen(vWF:Ag): 0.47-1.47 U/mL (Blood Group O) 0.54-1.76 U/mL (Other Blood Groups) In case of discrepancies, always interpret results using reference ranges as stated on laboratory reports and/or electronic patient chart.