Von Willebrand Factor Antigen
General Information
- Lab Name
- Von Willebrand Factor Ag
- Lab Code
- VWFAG
- Epic Name
- Von Willebrand Factor Antigen
- Description
Von Willebrand Factor (VWF) antigen is an immuno-turbidimetric assay based on the agglutination of latex microparticles coated with antibodies specific for VWF added to the patient's plasma. The antigen-antibody reaction increases the turbidity of the reaction medium which is measured photometrically. The degree of turbidity and absorbance is directly related to the function of VWF level present in the patient's plasma.
Von Willebrand disease is diagnosed with a group of tests (factor VIII activity, von Willebrand factor antigen, von Willebrand factor activity, collagen binding assay and multimer analysis) in the context of the patient's medical history and clinical presentation. Von Willebrand antigen can be used to monitor therapeutic efficacy of treatment with DDAVP (desmopressin) or von Willebrand factor concentrates in patients with vWD.
Like all antigenic tests, the vWF assay cannot detect the rare type 2 von Willebrand disease variants whose level of VWF antigen is normal.
- Synonyms
- Factor 8 Related Antigen, Factor VIII Related Antigen
- Components
Interpretation
- Method
Optical, Stago STA LIA vWF Antigen assay
- Reference Range
-
Units: %
Female Male Age Range Age Range 0- 50-200 0- 50-200 Effective date: 10/03/2006
- Interferences and Limitations
The presence of rheumatoid factor may lead to an over-estimation of the vWF level. The extremely rare presence of anti-bovine albumin or anti-rabbit antibodies in certain subjects may lead to an over-estimation of vWF level.
This assay is insensitive to hemoglobin (up to 5g/L), bilirubin (up to 150 mg/L) and unfractionated heparin and low molecular weight heparin (up to 2 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
- Receiving Instructions
UW-MT Instructions : Take specimen to UW-MT Coag lab 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.
- Misc Sendout
Performance
- Lab Department
- Coagulation(COAG)
- Frequency
- Run on Tuesday and Friday. Reported by end of day.
- Available STAT?
- Yes, with LMR approval
- Performing Location(s)
-
HMC Coagulation
206-520-4600325 9th Ave, Rm # GWH-47, Seattle, WA 98104-2420
Billing & Coding
- CPT Codes
- 85246
- LOINC
- 27816-8
- Interfaced Order Code
- UOW1513
- Interfaced Result Code
- UOW1513