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HelpTest Code FXI Factor XI Assay
Specimen Requirements
Submit only one of the following specimens
Specimen Type: Whole Blood
Container/Tube: 2 Light Blue Top (3.2% Sodium
Citrate)
Volume: 2 × 2.7mL Whole Blood (Tubes must be
full)
Collection Instructions: Send whole blood
specimens to laboratory immediately.
Specimen Type: Platelet Poor Plasma
Container/Tube: 2 Light Blue Top (3.2% Sodium
Citrate)
Submission Container/Tube:
Plastic Vial
Minimum Volume: 1.0mL 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 2 aliquots with minimum volume
of 1mL each.
4. Freeze the aliquots in well-closed plastic tubes
immediately.
Reference Interval
64 - 155 %
Days and Times Performed
Tuesday through Friday, TAT 10 working days
Methodology
Activated Partial Thromboplastin Clot-Based Assay
Service Code
12503
Update
Last updated 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
Profile Information
- Prothrombin Time
- Activated Partial Thromboplastin Time
- Factor XI Activity Level
Reflex Tests
- APTT mixing study if APTT is > 37.0 seconds
Alias
Factor XI Activity