Von Willebrand Antigen

SIM

20699 

CPT

85246 

Synonyms

vWF Antigen;Antigenic factor VIII 

Specimen Type

Plasma 

Container

Blue-top (sodium citrate) tube

Collection Instructions

Blood should be collected in a blue-top tube containing 3.2 % buffered sodium citrate. Evacuated collection tubes must be filled to completion to ensure a proper blood to anticoagulant ratio. The sample should be mixed immediately by gentle inversion at least six times to ensure adequate mixing of the anticoagulant with the blood. 
Do not draw from an arm with a heparin lock or heparinized catheter. 

Volume

Volume: 2 ml. 
Min. volume: 1 ml. 

Additional Information

Diagnose von Willebrand factor (vWF) deficiency

Patient Preparation

Avoid warfarin (Coumadin) therapy for two weeks and heparin therapy for two days prior to the test.

Specimen Processing Instructions

Separate plasma from cells ASAP, being careful not to disturb the cells.

Transport Requirements

Freeze

Specimen Stability

 Frozen :7 days 

Rejection Criteria

Gross hemolysis; clotted specimen; specimen not frozen; serum

Reference Range

Reference range accompanies report

Critical Value

Test Includes

Von Willebrand Antigen 

Methodology

Latex immunoagglutination assay (LIA). Patient plasma is mixed with vWF antibody-coated latex particles. Aggregation of the latex particles caused by vWF from the sample is measured photo-optically. 

Testing Frequency

LCA

086280 

Reviewed By

Lisa McBride                   

Reviewed Date

2/19/2018

Supplemental

* Denotes  Reference Lab Test