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von Willebrand Panel
MessageSendout, Mayo test code: AVWPR
Test Code
LAB1112
Alias/See Also
Coag
von Willebrand Profile
AVWPR
von Willebrand Profile
AVWPR
CPT Codes
85240, 85246, 85397
Preferred Specimen
3 mL plasma from 3 light blue (sodium citrate) tubes
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. If patient has been recently transfused, it is best to perform this study pretransfusion, if possible.
Minimum Volume
2 plastic vials each containing 1 mL
Instructions
1. Specimen must be collected prior to factor replacement therapy.
2. For complete instructions, see Coagulation Guidelines for Specimen Handling and Processing in Special Instructions.
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 degrees C or, ideally, < or =-40 degrees C.
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.
2. For complete instructions, see Coagulation Guidelines for Specimen Handling and Processing in Special Instructions.
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 degrees C or, ideally, < or =-40 degrees C.
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.
Transport Container
3 plastic vials
Transport Temperature
Frozen
Specimen Stability
Frozen: 14 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Gross hemolysis: Reject
Gross lipemia: Reject
Gross icterus: Reject
Gross lipemia: Reject
Gross icterus: Reject
Methodology
F8A: Optical Clot-Based
VWAG, VWACT: Latex Immunoassay (LIA)
FDA Status
Approved
Setup Schedule
F8A: Monday through Friday
VWAG, VWACT: Monday through Saturday
VWAG, VWACT: Monday through Saturday
Report Available
2-12 days
Limitations
Testing should be performed prior to and in the absence of recent transfusion or von Willebrand factor (VWF) replacement therapy, (eg, Humate P or DDAVP: desmopressin). If the patient has received any such therapy, this information should be provided. von Willebrand disease (VWD) patients receiving Humate P therapy may have a VWF activity level 10% to 20% lower than the VWF ristocetin cofactor activity level. Low normal levels of VWF antigen or activity do not exclude possible diagnosis of VWD (repeat testing may be indicated). Use of estrogens may result in a mild increase in VWF levels, thus masking a diagnosis of mild VWD.
Borderline low or slightly decreased levels of VWF antigen or activity may be observed in clinically normal individuals of blood group "O."
This test is not useful for differentiating type 2A versus 2B VWD or platelet-type VWD (pseudo-VWD). This differentiation requires ristocetin-induced platelet aggregation testing, which must be performed using freshly obtained patient platelets and plasma.
Clinical correlation is required for differentiating acquired from congenital (hereditary) forms of VWD. Repeat testing may be helpful for confirming or evaluating low or borderline low levels of VWF (antigen and activity), especially when there is strong suspicion of VWD.
The milder forms of the disease, especially type 1 VWD, can be difficult to diagnose or exclude, reflecting the variability of baseline VWF levels. In addition to demonstration of persistently decreased levels of VWF, clinical correlation is required for diagnosis of all VWD subtypes, especially mild type 1 VWD.
Borderline low or slightly decreased levels of VWF antigen or activity may be observed in clinically normal individuals of blood group "O."
This test is not useful for differentiating type 2A versus 2B VWD or platelet-type VWD (pseudo-VWD). This differentiation requires ristocetin-induced platelet aggregation testing, which must be performed using freshly obtained patient platelets and plasma.
Clinical correlation is required for differentiating acquired from congenital (hereditary) forms of VWD. Repeat testing may be helpful for confirming or evaluating low or borderline low levels of VWF (antigen and activity), especially when there is strong suspicion of VWD.
The milder forms of the disease, especially type 1 VWD, can be difficult to diagnose or exclude, reflecting the variability of baseline VWF levels. In addition to demonstration of persistently decreased levels of VWF, clinical correlation is required for diagnosis of all VWD subtypes, especially mild type 1 VWD.
Reference Range
Included with report
Clinical Significance
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.
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.
Performing Laboratory
Mayo Clinic Laboratories, Rochester, Minnesota
Additional Information
von Willebrand Disease Profile, Plasma
