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Test Code LAB3550 Von Willebrand Factor Activity

Important Note

For STAT requests, please contact the UW Lab Medicine Resident (LMR) for approval. Call UW Client Support Services (CSS) at (206) 520-4600 and ask for the LMR on call. If approved, notify Seattle Children's lab of approved STAT request.

Additional Codes

VWF SO

Clinical System Name

Von Willebrand Factor Activity

Synonyms

Ristocetin Cofactor Activity; Von Willebrand Factor Activity; VWF Activity

Sample Requirements

Specimen: Whole Blood

Container(s): Lt. Blue/Citrate

Preferred Vol: (1) 2.7 mL

Minimum Vol: (1) 1.8 mL

 

Note: Preferred method of collection is venipuncture with vacuum fill.  Test results are affected by incorrect blood volume.  Use of a Vascular Access Device for the  collection of coag testing is not recommended.

If this method is used it requires a 5 cc clearing volume; 3 cc for size 2 French catheter or smaller. Blood must be trasferred to the  Lt Blue/Citrate tube by use of a  blood transfer device to ensure proper fill. 

Specimen should be processed within one hour of collection. 

Processing Instructions

Deliver blood to Core Coag bench. Coag Technologist will process.

 

Reject due to: Clotted, hemolyzed, insufficient quantity, or improper collection.

Spin: Y

Aliquot: Y

Temp: -70 C

Storage Location: CPA 2 Freezer ( -70 C) Send Out rack.

 

Specimen should be centrifuged within one hour of collection. Transfer upper 3/4 layer of plasma to plastic tube affixed with large Epic aliquot label. Freeze one aliquot of plasma at -70 C. Preferred and minimum plasma volume: 1.0 mL. Do not pool. 

 

Off-site collection: Preferred method of collection is venipuncture with vacuum fill. Test results are affected by incorrect blood volumel. Use of a Vascular Access Device for the collection of coag testing is not recommended. If this method is used it requires a 5 cc clearing volume; 3 cc for size 2 French catheter or smaller. Blood must be trasferred to the Lt Blue/Citrate tube by use of the blood transfer device. 

Specimen should be centrifuged within one hour of collection. Transfer upper 3/4 layer of plasma to plastic tube affixed with large Epic aliquot label. Freeze one aliquot of plasma at -70 C. Preferred and minimum plasma volume: 1.0 mL. Do not pool. 

Stability

Specimen Type Temperature Time
Plasma Room temp N
  Refrigerated N
  Frozen Y

Availability

STAT Performed TAT
N T 7 - 10 d

 

Performing Laboratory

Harborview Medical Center

Coagulation Laboratory

325 9th Avenue, Room GWH 47

Seattle, WA 98104

 

Phone Number: Coagulation Lab - (206) 744-3128,  UW Client Support Services - (206) 520-4600

Department

Department: Send Outs

Phone Number: (206) 987-2563

CPT Codes

85245

Methodology

Method: Latex Immunoassay (LIA)

Analytical Volume: 1.0 mL Plasma

Limitations:

Reference Range

Units: %

Female Male
Age Range Age Range
0- 50-200 0- 50-200

Send Out Instructions

Reference Test Name: Von Willebrand Factor Activity
Reference Lab Test Code: VWFACT
Instructions: Send out Monday through Friday with the UW courier.