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HelpOrder Code LAB926 von Willebrand Disease Profile, Plasma
Additional Codes
Mayo Test Code: AVWPR
Ordering Guidance
Multiple coagulation profile tests are available. See Coagulation Profile Comparison for testing that is performed with each profile.
Shipping Instructions
Send all 3 aliquots in the same shipping container.
Necessary Information
1. If priority specimen, mark request form, give reason, and request a call-back.
2. Note if patient is currently receiving anticoagulant treatment (eg, heparin, Coumadin [warfarin]).
Specimen Required
Specimen Type: Platelet-poor plasma
Patient Preparation:
1. Patient should not be receiving anticoagulant treatment (eg, warfarin, heparin). Treatment with heparin causes false-positive results of in vitro coagulation testing for lupus anticoagulant. Coumadin (warfarin) treatment may impair ability to detect the more subtle varieties of lupus-like anticoagulants.
2. Patient should also not be receiving fibrinolytic agents (streptokinase, urokinase, tissue plasminogen activator[ tPA]).
3. It is best to perform this study pretransfusion if possible. If patient has been recently transfused, wait at least 48 hours after transfusion to collect the specimen.
Collection Container/Tube: Light-blue top (3.2% sodium citrate)
Submission Container/Tube: Plastic vials
Specimen Volume: 3 mL in 3 plastic vials, each containing 1 mL
Collection Instructions:
1. Specimen must be collected prior to factor replacement therapy.
2. For complete instructions, see Coagulation Guidelines for Specimen Handling and Processing.
3. Centrifuge, transfer all plasma into a plastic vial, and centrifuge plasma again.
4. Aliquot plasma (1-2 mL per aliquot) into 3 separate plastic vials, leaving 0.25 mL in the bottom of centrifuged vial.
5. Freeze plasma immediately (no longer than 4 hours after collection) at -20° C or, ideally, -40° C or below.
Additional Information:
1. Double-centrifuged specimen is critical for accurate results as platelet contamination may cause spurious results.
2. Each coagulation assay requested should have its own vial.
Forms
1. Coagulation Patient Information (T675)
2. If not ordering electronically, complete, print, and send a Coagulation Test Request (T753) with the specimen.
Useful For
Detection of deficiency or abnormality of von Willebrand factor (VWF) and related deficiency of factor VIII coagulant activity
Subtyping von Willebrand disease (VWD) as type 1 (most common), type 2 variants (less common), or type 3 (rare)
This test is not useful for detection of hemophilia carriers.
Profile Information
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| AVWPI | von Willebrand Disease Tech Interp | No | Yes |
| F8A | Coag Factor VIII Activity Assay, P | Yes | Yes |
| VWAG | von Willebrand Factor Ag, P | Yes | Yes |
| VWACT | von Willebrand Factor Activity, P | Yes | Yes |
Testing Algorithm
Initial testing includes coagulation factor VIII activity assay, von Willebrand factor (VWF) antigen, VWF activity and interpretation.
If the factor VIII, VWF antigen, VWF activity, and VWF activity:VWF antigen ratio results are normal, then a computer-generated interpretive comment indicating no evidence of von Willebrand disease will be provided.
If VWF activity assay is less than 55% or VWF activity:VWF antigen ratio is abnormally increased, then VWF ristocetin cofactor activity assay will be performed at an additional charge.
If VWF antigen is less than 55%, the VWF activity is less than 55%, or the VWF activity:VWF antigen ratio is abnormally low, then VWF multimer analysis will be performed at an additional charge.
If any test results are abnormal, all results will be reviewed by a coagulation consultant and a von Willebrand Disease Interpretation will be provided at an additional charge.
For more information see von Willebrand Disease Profile.
Special Instructions
Method Name
AVWPI: Technical Interpretation
F8A, F8A, 8BETH: Optical Clot-Based
RIST: Ristocetin-Induced Agglutination
VWAG, VWACT: Latex Immunoassay (LIA)
VWFMP: Agarose Gel Electrophoresis/Infrared Dye-Labeled Antibody Detection
Reporting Name
von Willebrand Disease ProfSpecimen Type
Plasma Na CitSpecimen Minimum Volume
2 Plastic vials, each containing 1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Plasma Na Cit | Frozen | 14 days |
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
| Gross icterus | Reject |
Reference Values
An interpretive report will be provided.
Method Description
von Willebrand Factor Antigen
This assay is performed using the HemosIL von Willebrand Factor Antigen kit on the Instrumentation Laboratory ACL TOP. This is a latex immunoassay method using microlatex particles coated with specific rabbit-polyclonal antibody directed against von Willebrand factor (VWF). In the presence of VWF antigen, antibody-coated latex particles agglutinate to form aggregates of diameters greater than the wavelength of the light passing through the sample and more light is absorbed as aggregation increases. The increase in absorption is proportional to the concentration of VWF antigen present in the sample.(Package insert: HemosIL von Willebrand Factor Antigen, Instrumentation Laboratory, R11 05/2018)
von Willebrand Factor Activity
This is a latex particle-enhanced immunoassay to quantify VWF activity in plasma. The activity of VWF is determined by measuring the increase of turbidity produced by the agglutination of the latex reagent. A specific anti-VWF monoclonal antibody adsorbed onto the latex reagent, directed against the platelet-binding site of VWF (glycoprotein Ib receptor), reacts with the VWF of patient plasma. The degree of agglutination is directly proportional to the activity of VWF in the sample and is determined by measuring the decrease of transmitted light caused by the aggregates.(Package insert: HemosIL von Willebrand Factor Activity, Instrumentation Laboratory, Â R7 05/2018)
Factor VIII Activity
The factor VIII assay is performed on the Instrumentation Laboratory ACL TOP using the activated partial thromboplastin time (APTT) method and a factor-deficient substrate. Patient plasma is combined and incubated with a factor VIII-deficient substrate (normal plasma depleted of factor VIII by immunoadsorption) and an APTT reagent. After a specified incubation time, calcium is added to trigger the coagulation process in the mixture. Then the time to clot formation is measured optically at a wavelength of 671 nm.(Owen CA Jr, Bowie EJW, Thompson JH Jr. Diagnosis of Bleeding Disorders. 2nd ed. Little, Brown and Company; 1975; Cielsa B. Defects of plasma clotting factors. In: Hematology in Practice. 3rd ed. FA Davis; 2019:chap 17)
Day(s) Performed
Monday through Friday
Performing Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
85240-Coagulation factor VIII assay
85246-von Willebrand factor antigen
85397-von Willebrand factor activity
85245-von Willebrand factor ristocetin cofactor activity (if appropriate)
85247-von Willebrand factor multimer (if appropriate)
85335-Bethesda titer (if appropriate)
85335-Coagulation factor VIII inhibitor screen (if appropriate)
85390-26-Special coagulation interpretation (if appropriate)
Reflex Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| F8IS | Coag Factor VIII Assay Inhib Scrn,P | No | No |
| AVWPQ | von Willebrand Disease Interp | No | No |
| VWFMP | von Willebrand Factor Multimer, P | Yes, (order VWFMS) | No |
| RIST | Ristocetin Cofactor, P | No | No |
| 8BETH | FVIII Bethesda Units, P | No | No |