Ordering Recommendation

Molecular testing to distinguish von Willebrand disease (VWD) type 2B from pseudo (platelet-type) VWD.

Mnemonic
GP1BA SEQ
Methodology

Polymerase Chain Reaction/Sequencing/Fragment Analysis

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, Platelet Type (GP1BA) 4 Mutations:
Characteristics
: Mild to moderate mucocutaneous bleeding after brushing or flossing teeth, unexplained bruising, prolonged repeated nosebleeds, menorrhagia, and prolonged bleeding following childbirth, trauma or surgery. Thrombocytopenia may be present and worsen during the stress of severe infection, surgery or pregnancy.
Incidence:  Very rare.
Inheritance: Autosomal dominant. 
Cause: Pathogenic GP1BA mutations.
Clinical Sensitivity: Unknown.
Methodology: Targeted bidirectional sequencing of the GP1BA gene mutations  c.746G>T (p.Gly249Val), c.746G>A (p.Gly249Ser), and c.763A>G (p.Met255Val); PCR followed by fragment analysis of c.1306del27 (p.436_444del9).
Limitations: Diagnostic errors can occur due to rare sequence variations. Regulatory region mutations, deep intronic mutations, and large deletions/duplications will not be detected. GP1BA mutations other than the four targeted, will not be evaluated.

Compliance Category

Laboratory Developed Test (LDT)

Note
Hotline History
N/A
CPT Codes

81400

Components
Component Test Code* Component Chart Name LOINC
2005477 VWD Platelet Type (GP1BA) Seq Spcm
2005478 VWD PlatletType (GP1BA) Seq 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
  • GP1BA Sequencing
  • Platelet Type Von Willebrand Disease (vWD)
  • Pseudo Von Willebrand Disease (vWD)
  • Von Willebrand Disease (vWD) Platelet Type
  • VWD Platelet Type 4
von Willebrand Disease, Platelet Type (GP1BA) 4 Mutations