Ordering Recommendation

Molecular testing to distinguish von Willebrand disease type 2N from hemophilia A.

Mnemonic

VWF2N SEQ

Methodology

Polymerase Chain Reaction/Sequencing

Performed

Varies

Reported

14-21 days

New York DOH Approval Status

Specimens from New York clients will be sent out to a New York DOH approved laboratory, if possible.

Specimen Required

Patient Preparation
Collect

Lavender (EDTA), pink (K2EDTA) or yellow (ACD Solution A or B).

Specimen Preparation

Transport 3 mL whole blood. (Min: 1 mL)

Storage/Transport Temperature

Refrigerated.

Unacceptable Conditions
Remarks
Stability

Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable

Reference Interval

By report

Interpretive Data

Background Information for von Willebrand Disease, Type 2N (VWF) Sequencing:
Characteristics
: Mucocutaneous bleeding after brushing or flossing teeth, unexplained bruising, prolonged repeated nosebleeds, menorrhagia, and prolonged bleeding following childbirth, trauma or surgery. Symptoms of type 2N are similar to mild hemophilia A.
Incidence: Approximately 1 in 100 to 1 in 1000 individuals.
Inheritance: Autosomal recessive.
Cause: Pathogenic VWF mutations.
Clinical Sensitivity: Unknown for VWD type 2N.
Methodology: Bidirectional sequencing of VWF exons 4, 9, 17, 18, 19, 20, 21, 24, 25, and 27 and the corresponding intron-exon boundaries.
Analytical Sensitivity and Specificity: 99 percent.
Limitations: Diagnostic errors can occur due to rare sequence variations. Regulatory region mutations, deep intronic mutations, and large deletion/duplications will not be detected.  Mutations lying outside of VWF exons 4, 9, 17, 18, 19, 20, 21, 24, 25, and 27 will not be evaluated.

This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes.

Counseling and informed consent are recommended for genetic testing. Consent forms are available online.

Compliance Category

Laboratory Developed Test (LDT)

Note

Hotline History

N/A

CPT Codes

81405

Components

Component Test Code* Component Chart Name LOINC
2005495 VWD Type 2N (VWF) Sequencing Specimen
2005496 VWD Type 2N (VWF) Sequencing Interp
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.

Aliases

  • VWD type 2N sequencing assay
  • VWF2N Sequencing
von Willebrand Disease, Type 2N (VWF) Sequencing (Temporary Referral as of 02/10/21)