von Willebrand Disease, Type 2A (VWF) Sequencing Exon 28 with Reflex to 9 Exons
2005480
Ordering Recommendation
Molecular testing to confirm a phenotypic diagnosis of von Willebrand disease type 2A.
Mnemonic
VWF2A SEQ
Methodology
Polymerase Chain Reaction/Sequencing
Performed
Varies
Reported
Within 28 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 2A (VWF) Sequencing Exon 28 with Reflex to 9 Exons.
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.
Clinical Sensitivity
: 99 percent for vWD type 2A and 80 percent for types 2B and 2M; unknown for other vWD subtypes.
Methodology:
Bidirectional sequencing of VWF exon 28 and its intron-exon boundaries; if no pathogenic mutations are detected, bidirectional sequencing of exons 11, 12, 14, 15, 16, 24, 25, 51, and 52 and the corresponding intron-exon boundaries is performed.
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 11, 12, 14, 15, 16, 24, 25, 28, 51 and 52 are not evaluated.






See Compliance Statement C: www.aruplab.com/CS
Statement C: The performance characteristics of this test were validated by ARUP Laboratories. The U.S. Food and Drug Administration (FDA) has not approved or cleared this test; however, FDA approval or clearance is currently not required for clinical use of this test. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions. ARUP is authorized under Clinical Laboratory Improvement Amendments (CLIA) and by all states to perform high-complexity testing.

Counseling and informed consent are recommended for genetic testing. Consent forms are available online.
 
Note
Exon 28 sequencing is performed on all samples. If results do not explain the clinical scenario, then sequencing of 9 exons (11, 12, 14, 15, 16, 24, 25, 51 and 52) will be added. Additional charges apply.
CPT Code(s)
81403; If reflexed, add 81405
Components
Component Test Code*Component Chart Name
2005481vWD Type 2A (VWF) Sequencing Specimen
2005482vWD Type 2A (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 platelet type 2A reflex
  • VWF2A Sequencing