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HelpTest Code VWD von Willebrand's Disease
Specimen Requirements
Submit only one of the following specimens
Specimen Type: Whole Blood
Container/Tube: 4 Light Blue Top (3.2% Sodium
Citrate)
Volume: 4 × 2.7mL Whole Blood (Tubes
must be full)
Collection Instructions: Send whole blood
specimens to laboratory immediately.
Specimen Type: Platelet Poor Plasma
Container/Tube: 4 Light Blue Top (3.2% Sodium
Citrate)
Submission Container/Tube: Plastic Vial
Minimum Volume: 4.0mL Plasma
Collection Instructions:
1. Light blue top tube must be properly filled with whole
blood.
2. Whole blood specimen should be double centrifuged and plasma
separated from cells within 1 hour of collection.
3. Plasma should be separated into 4 aliquots with minimum
volume of 1mL each.
4. Freeze the aliquots in well-closed plastic tubes
immediately.
Reference Interval
Clinical interpretive report will be provided.
Days and Times Performed
Friday, TAT 15 working days
Methodology
Photo-optical Clot Detection, Immunoturbidimetric Assay
Service Code
12500 (Factor VIII Assay)
12013 (von Willebrand Factor Antigen)
12021 (Ristocetin Cofactor)
Update
02/05/2017
Unacceptable Condition
| Haemolysis | Gross reject |
|---|---|
| Icterus | Gross reject |
| Lipaemic | Gross reject |
| Others | Clotted or insufficient reject |
Specimen Stability
**Preferred temperatures for storage prior to and during shipping to NUH**
| Specimen Type | Plasma |
|---|---|
| Ambient | 4 hours |
| Refrigerate | NA |
| Frozen | 14 days |
Testing Laboratory
National University Hospital
Haematology, 67725320
Useful For
Aids in the diagnosis of von Willebrand’s Disease.
Profile Information
- Prothrombin Time
- Activated Partial Thromboplastin Time
- Factor VIII Assay
- von Willebrand Factor Antigen
- Ristocetin Cofactor
Reflex Tests
- APTT mixing study if APTT is > 37.0 seconds
Alias
vWD
Factor VIII
FVIII
vWF
vWF:Ag
Ristocetin Cofactor Activity
RCF
Ricof
Ristocetin
vWF Activity