Home
HelpTest Code LAB1235528 von Willebrand Factor Antigen, Plasma
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Reporting Name
von Willebrand Factor Ag, PSpecimen Type
Plasma Na CitOrdering Guidance
For optimum clinical utility and diagnostic efficiency, this test's results generally must be used together with the results of the von Willebrand factor ristocetin cofactor activity and factor VIII coagulant activity tests. The diagnosis of von Willebrand disease requires a combination of clinical and laboratory information. For a streamlined approach to testing, a panel of tests with reflexive testing and interpretive reporting is recommended. See AVWPR / von Willebrand Disease Profile, Plasma.
Additional Testing Requirements
VWACT / von Willebrand Factor Activity, Plasma and F8A / Coagulation Factor VIII Activity Assay, Plasma are recommended in conjunction with this test (von Willebrand antigen).
Specimen Required
Specimen Type: Platelet-poor plasma
Collection Container/Tube: Light-blue top (3.2% sodium citrate)
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions:
1. For complete instructions, see Coagulation Guidelines for Specimen Handling and Processing.
2. Centrifuge, transfer all plasma into a plastic vial, and centrifuge plasma again.
3. Aliquot plasma into a plastic vial, leaving 0.25 mL in the bottom of centrifuged vial.
4. Freeze plasma immediately (no longer than 4 hours after collection) at -20° C or, ideally, less than or equal to -40° 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.
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
| Gross icterus | Reject |
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Plasma Na Cit | Frozen | 14 days |
Specimen Minimum Volume
0.5 mL
Special Instructions
Day(s) Performed
Monday through Saturday
Specimen Retention Time
7 daysReport Available
1 to 3 daysReference Values
55-200%
Note: Individuals of blood group "O" may have lower plasma von Willebrand factor (VWF) antigen than those of other ABO blood groups, such that apparently normal individuals of blood group "O" may have plasma VWF antigen as low as 40% to 50%, whereas the lower limit of the reference range for individuals of other blood groups may be 60% to 70%.
Children: Neonates, infants, and children have normal or mildly increased plasma VWF antigen, with respect to the adult reference range.
Useful For
Diagnosis of von Willebrand disease (VWD) and differentiation of VWD subtype (in conjunction with von Willebrand factor ristocetin cofactor activity and factor VIII coagulant activity)
Differentiation of VWD from hemophilia A (in conjunction with factor VIII coagulant assay)
Monitoring therapeutic efficacy of treatment with DDAVP (desmopressin) or von Willebrand factor concentrates in patients with VWD
CPT Code Information
85246
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| VWAG | von Willebrand Factor Ag, P | 27816-8 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| VWAG | von Willebrand Factor Ag, P | 27816-8 |
Supportive Data
Mayo studies demonstrate excellent concordance between the enzyme-linked immunosorbent assay and this automated latex immunoassay (LIA) (r[2]=0.95) in about 80 patient specimens (with von Willebrand factor: VWF antigen ranging from 3% to 800%), and satisfactory concordance between VWF antigen by LIA and ristocetin cofactor activity (r[2]=0.88).
Forms
If not ordering electronically, complete, print, and send a Coagulation Test Request (T753) with the specimen.