ARUP's Laboratory Test Directory

von Willebrand Disease, Type 2N (VWF) Sequencing : 2005494
[ image for: Patient History for von Willebrand (VWD) Testing]
Patient History for von Willebrand (VWD) Testing
[ image for: Additional Technical Information]
Additional Technical Information


Mnemonic: VWF2N SEQ

Ordering Recommendation: Molecular testing to distinguish von Willebrand disease type 2N from hemophilia A.
Methodology: Polymerase Chain Reaction/Sequencing
Performed: Varies
Reported: Within 21 days
Specimen Required: 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.

Stability (collection to initiation of testing): 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
: Rare diagnostic errors can occur due to primer site mutations. 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.



Counseling and informed consent are recommended for genetic testing. Consent forms are available online at www.aruplab.com.

See Compliance Statement C: www.aruplab.com/CS
CPT Code(s): 81405
Cross References: VWF2N  Sequencing