Laboratory Services

Von Willebrand Factor Activity

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Updated Test Information:

Test Description
Von Willebrand Factor Activity
Synonym(s)

Ristocetin Cofactor Alternative, VWF Activity, UOW843

Test ID
VWFACT
General Information

VWF activity is measured using latex particles coated with purified anti-vWF mouse monoclonal antibody directed against the platelet binding site of VWF (the glycoprotein Ib receptor). This assay is used instead of the ristocetin cofactor assay due to better assay performance.


Clinical assay interference and limitations: The presence of rheumatoid factor may produce an overestimation of the vWF level. The presence of HAMA (human anti-mouse antibody) may lead to an over-estimation of vWF level using this assay.

Container Type

3 or 5 mL BLUE TOP (CITRATE) tube

Specimen Type

Plasma

Specimen Requirements

Sample must be centrifuged, aliquoted and frozen within 4 hours of collection

Specimen Collection / Processing Instructions

Centrifuge for 10 minutes, remove plasma & re-spin plasma for another 10 minutes. Decant & Freeze plasma (minimum 1.0 mL) @ -20°C to -80°C. Send frozen on dry ice.

Stability

Frozen

Department (code)

Coagulation

Methodology

Latex Immunoassay (LIA)

Testing Schedule

Tuesday

CPT Code(s)

85245

Reference Range

Units: %


Male/Female


50-200


Effective date: 10/03/2006

Performing Lab

UW

LOINC Code(s)