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Test Code HEM4 Von Willebrand Factor Ag

Clinical Information

Aid with the diagnosis of von Willebrand disease.

Synonym

  • VWFAG
  • vWF Antigen
  • vWF Immunologic

Specimen Required

Preferred Container/Tube: 3.2% Citrate Blue Top - 2.7 mL
Specimen Volume: 2.7 mL
Acceptable Container/Tube: 3.2% Citrate Blue Top - 1.8 mL
Specimen Volume: 1.8 mL
Platelet poor plasma (PPP):
Specimen Volume: 2 - 1 mL aliquots platelet poor plasma (PPP)
Specimen Minimum Volume: 1 - 1 mL aliquot platelet poor plasma (PPP)

Specimen Collection Information

For Outreach, other than OSU Patient Service Centers: Samples must be processed and received frozen/must remain frozen in transit. 

For sending frozen plasma specimens, process immediately upon receipt. Centrifuge capped specimen tube in accordance with CLSI H21, at a speed and time required to consistently produce platelet-poor plasma (PPP = platelet count <10 K/uL). Transfer PPP into plastic aliquot tubes, cap and freeze. DO NOT transport until specimens are completely frozen. 

Specimen Stability Information

Ambient: 
     Whole blood: 4 hours
      Platelet poor plasma: 8 hours
Frozen: 
      Platelet poor plasma: PPP removed from the cells and frozen at -20°C or ideally -70°C.

Rejection Due To

  • Ambient WB specimens >4 hours old
  • Ambient PPP specimens >8 hours old
  • Clotted specimens
  • Underfilled or overfilled tube
  • Hemolysis

Reference Values

0-4 days: 50-287 %
5-29 days: 50-254 %
30-89 days: 50-246 %
90-179 days: 50-206 %
180-365 days: 50-197 %
1-5 years: 60-120 %
6-10 years: 44-144 %
11-16 years: 46-153 %
17+ years: 50-180 %

Cautions

vWF disease necessitates a series of clinical and laboratory evaluations including patient and family history, vWF activity, factor VIII activity, and von Willebrand factor antigen.

Method Description

Immuno-turbidimetric method (STA - Liatest VWF:Ag)

Performing Lab

Clinical Lab UH

Day(s) Performed

Monday through Friday (excludes OSU holidays)

Report Available

Same day/1 day

Reporting Name

Von Willebrand Factor Antigen

CPT Code Information

85246

LOINC Code Information

27816-8