|Also Known as (Alias)||VWD genotyping|
|Method||polymerase chain reaction (PCR) based|
|Test Information||Von Willebrand Disease (VWD) is one of the most common inherited bleeding disorders. This disorder is divided into three types, Type 1, Type 2 and Type 3. All types of this condition cause prolonged bleeding episodes of varying severity; Type 1 is the mildest of the three types and Type 3 is the most severe. Type 2 is intermediate in severity and is further divided into four subtypes. Type 2A VWD is the most common form of Type 2, accounting for 70% of the Type 2 diagnosis
Mutations in the von Willebrand Factor (VWF) gene cause VWD. This disease can have different inheritance patterns. Type 1 and Type 2 (2A, 2B, and 2M) are inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. Type 3 and Type 2N are inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations.
|Additional Test Information||The Von Willebrand Factor Screen sequences up to 9 exons for mutations depending on the type. Confirmation is performed one of two ways. If the mutation creates/removes a restriction enzyme digestion site, the testing will be performed by RFLP. If a restriction enzyme digestion site is not present, testing will be done by sequencing the exon in which the mutation is located|
|Sample Requirements||EDTA (lavender top)|
|Requested Volume||5-10cc EDTA (lavender top) tube OR
Analysis of amniocytes can be performed on cultured amniocytes. Two T-25 flasks of cells cultured to confluency will be accepted. Bloodworks Northwest does not have facilities to culture amniocytes. Bloodworks Northwest does not have facilities to culture amniocytes.
|Shipping Information||Whole blood shipped at 4oC or ambient temperature is acceptable and should arrive in the lab within 48 hours.
Send samples to:
|Requisition Form||Request for Testing Hemostasis Reference Laboratory|
|Turn around Time (analytic time)||5-10 business days|
|Report/Results||Fax number required to receive report|
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