Laboratory Services
Von Willebrand Factor Activity
Print this pageUpdated Test Information:
Test Description |
Von Willebrand Factor Activity
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Synonym(s) |
Ristocetin Cofactor Alternative, VWF Activity, UOW843 |
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Test ID |
VWFACT
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General Information |
VWF activity is a turbidimetric latex bead-based assay that measures the binding of von Willebrand factor (VWF) to platelet receptor glycoprotein Ib (GPIb) without ristocetin. The diagnosis or exclusion of any type of von Willebrand disease should never be based solely on the VWF activity result. This test should always be interpreted in conjunction with a group of tests (Factor VIII activity, VWF antigen, collagen binding activity and multimer analysis) in the context of the patient's medical history and clinical presentation. Von Willebrand activity can be used to monitor therapeutic efficacy of treatment with DDAVP (desmopressin) or von Willebrand factor concentrates in patients with von Willebrand disease. |
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Container Type |
3 mL or 5 mL Light Blue Citrate Tube |
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Specimen Type |
Plasma |
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Specimen Requirements |
Sample must be centrifuged, aliquoted and frozen within 4 hours of collection |
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Specimen Collection / Processing Instructions |
MUST PROCESS WITHIN 4 HOURS OF COLLECTION |
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Minimum Sample Volume |
1 mL |
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Stability |
Frozen |
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Limitations |
The presence of rheumatoid factor or human anti-mouse antibody (HAMA) may give a falsely elevated (observed more often) or depressed result. This assay is not affected by unconjugated bilirubin up to 60 mg/dL, conjugated bilirubin up to 40 mg/dL, triglycerides up to 726 mg/dL and rheumatoid factor up to 438 IU/mL. |
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Department (code) |
Coagulation |
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Methodology |
Innovance VWF:GPIbM Latex-Immunoassay |
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Testing Schedule |
Tuesday |
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CPT Code(s) |
85245 |
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Reference Range |
Units: % Male/Female 50-200 Effective date: 10/03/2006 |
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Performing Lab |
UW |
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LOINC Code(s) |