von Willebrand Disease 2N (Subtype Normandy), Plasma
Use
This test is useful for diagnosing von Willebrand disease (VWD) type 2N. It is particularly useful in evaluating patients diagnosed with mild-to-moderate hemophilia A with an autosomal inheritance pattern, evaluating hemophilia A patients with a shortened survival of infused factor VIII (FVIII) not caused by a specific FVIII inhibitor, evaluating female patients with low FVIII activity and no prior family history of hemophilia A, and evaluating patients with Type 1 or Types 2A, 2B, or 2M VWD with FVIII activity discordantly lower than the von Willebrand factor antigen level.
Special Instructions
Ensure that additional testing requirements are met by conducting supplementary tests like von Willebrand Factor Antigen, Plasma; von Willebrand Factor Activity, Plasma; and Coagulation Factor VIII Activity Assay, Plasma along with this test. Double-centrifuged plasma specimens are crucial for accurate results to prevent platelet contamination.
Limitations
Genetic tests screening for variants causing VWD type 2N, although available, come with limitations such as being expensive and potentially missing variants located in regions not covered by the molecular assays. Additionally, subjects with antirabbit antibodies may experience confounding results. A von Willebrand Factor antigen level greater than or equal to 15% is necessary for accurate interpretation of results.
New York Approved
Methodology
Immunoassay (ELISA)
Biomarkers
LOINC Codes
- 90919-2
- 90919-2
- 48595-3
Result Turnaround Time
1-31 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
1 mL
Minimum Volume
0.5 mL
Container
Light-blue top (3.2% sodium citrate)
Collection Instructions
Centrifuge, transfer all plasma into a vial, and centrifuge plasma again. Aliquot plasma into a separate tube leaving 0.25 mL in the bottom of the centrifuged vial. Freeze plasma immediately (no longer than 4 hours after collection) at -20 degrees C or, ideally, less than or equal to -40 degrees C.
Causes for Rejection
Gross hemolysis, Gross lipemia, Gross icterus (all OK)
Stability Requirements
| Temperature | Period |
|---|---|
| Frozen | 56 days |