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Test ID VWD8B von Willebrand Disease 2N (Subtype Normandy), Plasma


Additional Testing Requirements


VWAG / von Willebrand Factor Antigen, Plasma; VWFX / von Willebrand Factor Activity, Plasma and F8A / Coagulation Factor VIII Activity Assay, Plasma are recommended to supplement results of this test.



Necessary Information


If performed at another laboratory, forward the results of the following tests with the specimen:

-von Willebrand factor (VWF) antigen

-VWF activity (ristocetin cofactor, latex immunoassay etc)

-Factor VIII (FVIII) activity

 

These results aid in the interpretation of this test.



Specimen Required


See Coagulation Guidelines for Specimen Handling and Processing in Special Instructions.

 

Specimen Type: Platelet-poor plasma

Collection Container/Tube: Light-blue top (3.2% sodium citrate)

Submission Container/Tube: Polypropylene vial

Specimen Volume: 1 mL

Collection Instructions: Centrifuge, remove plasma, and centrifuge plasma again.

1. Aliquot plasma into a separate tube leaving 0.25 mL in the bottom of the centrifuged vial.

2. Freeze plasma immediately (no longer than 4 hours after collection) at ≤-20° C, or, ideally ≤ -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.


Forms

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

Useful For

Diagnosis of von Willebrand disease (VWD) type 2N

 

Evaluation of patients diagnosed with mild-to-moderate hemophilia A with an autosomal inheritance pattern

 

Evaluation of hemophilia A patients with a shortened survival of infused factor VIII (FVIII) (not caused by a specific FVIII inhibitor)

 

Evaluation of female patients with low FVIII activity and no prior family history of hemophilia A

 

Evaluation of patients with Type 1 or Types 2A, 2B, or 2M VWD with FVIII activity discordantly-lower than the von Willebrand factor antigen level

Highlights

This test is the most cost effective test for diagnosis of von Willebrand Factor (VWF): Factor VIII (FVIII) binding defects.

 

Genetic tests screening for variants that cause von Willebrand disease (VWD) type 2N are available. Limitations of genetic testing include expense and the potential for variants causing VWD 2N in regions not covered by the molecular assays.

Method Name

Enzyme-Linked Immunosorbent Assay (ELISA)

Reporting Name

VWD 2N (Normandy), P

Specimen Type

Plasma Na Cit

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Plasma Na Cit Frozen 56 days

Reference Values

68-106%

Pediatric reference ranges have not been established for this assay but likely achieve adult reference range by 18 years of age.

Day(s) and Time(s) Performed

Thursday; 8 a.m.

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics 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.

CPT Code Information

85246

LOINC Code Information

Test ID Test Order Name Order LOINC Value
VWD8B VWD 2N (Normandy), P In Process

 

Result ID Test Result Name Result LOINC Value
607336 VWF:FVIIIB 90919-2
607337 VWF:FVIIIB Interpretation 48595-3

NY State Approved

Yes