Days Set Up
Friday
Analytic Time

1 hour

MiChart Code
Von Willebrand Antigen
Soft Order Code
VWF

Test Updated:

Synonyms

Coagulation Ristocetin Co-Factor Activity
Ristocetin Co-Factor Activity
VWF
RISTOCETIN COFACTOR ASSAY

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Test Overview

Test Methodology

Platelet agglutination using washed platelets in the presence of ristocetin.

Test Usage

Aid with the diagnosis of von Willebrand disease.

Reference Range

50 - 150%

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Specimen Requirements

Collection Instructions

Collect specimen in a blue top (citrate 3.2%) tube. Mix by inversion. Specimen should arrive at lab within 3 hours of collection; transport at room temperature. Alternatively, centrifuge, aliquot plasma into a plastic vial, and freeze the specimen within 4 hours of collection. Transport frozen specimen on dry ice. Collection of the blood through lines that have been previously flushed with heparin should be avoided. If the blood must be drawn through a VAD (vascular access device), the line should be flushed with 5 mL of saline and the first 5 mL of blood or six dead space volumes of the VAD discarded.

Blue Top Tube
Normal Volume
Full 2.7mL tube or 1mL plasma aliquot
Minimum Volume
Full 1.8mL tube or 1mL plasma aliquot

Billing Information

CPT Code
85245
Pro Fee Code
 
Insurance Auth Info
 
LOINC
6014-5

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Our High Standard

Quality that sets us apart

As the reference laboratory division of Michigan Medicine's Department of Pathology, MLabs shares the institution's commitment to applying established quality principles to clinical laboratory testing. Like other large organizations in complex, consequential fields, we rely on an established approach to monitor quality throughout the testing process.