Laboratory Test Guide

Von Willebrand Factor Activity

General Information

Lab Name

VWF Activity

Lab Code

VWFACT

Epic Name

Von Willebrand Factor Activity

Description

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.

Synonyms

Ristocetin Cofactor Alternative, VWF Activity, VWF GPIbM activity

Interpretation

Method

Innovance VWF:GPIbM Latex-Immunoassay

Reference Range

Units: %

Female Male
AgeRangeAgeRange
0-50-200 0-50-200

Effective date: 10/03/2006

Interferences and 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.

Ordering & Collection

Specimen Type

Blood

Collection

3 or 5 mL BLUE TOP (CITRATE) tube

Handling Instructions

The Laboratory MUST process specimen within 4 hrs of blood collection.

Quantity

requested: Entire Sample

Processing

UW-MT Instructions: Take specimen to UW-MT Coag for processing. Coag tech will freeze plasma sample for transport to HMC Coag.

HMC Instructions: Take specimen to HMC Coag lab for processing.

Outside Laboratory: 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.

Performance

LIS Dept Code

Coagulation (COAG)

Performing Location(s)

HMC Coagulation
206-520-4600

325 9th Ave, Rm # GWH-47, Seattle, WA 98104-2420

Frequency

Run on Tuesday and Friday. Reported by end of day.

Available STAT?

Yes, with LMR approval

Billing & Coding

CPT codes

85245

LOINC

68324-3

Interfaced Order Code

UOW843

Interfaced Result Code

UOW843