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Test Code VWFAGM von Willebrand Factor Antigen, Plasma

Additional Codes








Reporting Name

von Willebrand Factor Ag, P

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 VWF concentrates in patients with VWD

Method Name

Automated Latex Immunoassay (LIA)

Performing Laboratory

Mayo Medical Laboratories in Rochester

Specimen Type

Plasma Na Cit

Additional Testing Requirements

VWFX / 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

See Coagulation Studies in Special Instructions.


Specimen Type: Platelet-poor plasma

Collection Container/Tube: Light-blue top (citrate)

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collection Instructions:

1. Spin down, remove plasma, and spin plasma again.

2. Freeze specimen immediately at ≤-40° C, if possible.

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.

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time
Plasma Na Cit Frozen 14 days

Reject Due To


Mild OK; Gross reject


Mild OK; Gross reject






Special Instructions

Reference Values


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.

Day(s) and Time(s) Performed

Monday through Saturday

CPT Code Information


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

Test Classification

This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

Analytic Time

1 day


If not ordering electronically, complete, print, and send a Coagulation Test Request Form (T753) with the specimen (