von Willebrand Disease, Type 2B (VWF) Sequencing (Temporary Referral as of 02/10/21)
Molecular testing to confirm a phenotypic diagnosis of von Willebrand disease type 2B and to distinguish from pseudo (platelet-type) VWD.
Polymerase Chain Reaction/Sequencing
New York DOH Approval Status
Lavender (EDTA), pink (K2EDTA) or yellow (ACD Solution A or B).
Transport 3 mL whole blood. (Min: 1 mL)
Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
Background Information for von Willebrand Disease, Type 2B (VWF) Sequencing:
Characteristics: Mucocutaneous bleeding after brushing or flossing teeth, unexplained bruising, prolonged repeated nosebleeds, menorrhagia, and prolonged bleeding following childbirth, trauma or surgery.
Incidence: Approximately 1 in 100 to 1 in 1000 individuals.
Inheritance: Autosomal dominant for types 2B, 2M and most of 2A; autosomal recessive for 20 percent of 2A.
Penetrance: Dominant mutations are incompletely penetrant when VWF:Ag and VWF:RCo levels are 25-50 IU/dL. Full penetrance is expected when VWF:Ag and VWF:RCo levels are less than 25 IU/dL.
Cause: Pathogenic VWF mutations in exon 28.
Clinical Sensitivity: 80 percent for vWD types 2A, 2B, and 2M; unknown for other vWD subtypes.
Methodology: Bidirectional sequencing of VWF exon 28 and its 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 exon 28 are not 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.
Laboratory Developed Test (LDT)
|Component Test Code*||Component Chart Name||LOINC|
|2005487||vWD2B (VWF) Specimen|
|2005488||vWD Type 2B (VWF) Sequencing Interp|
- VWD type 2B sequencing assay
- VWF2B Sequencing