Coagulation Factor Assays
Department of Haematology
Notes
- Prolongation of the coagulation screen that can be significantly corrected by the addition of normal patient plasma may be the result of a specific factor deficiency.
- Specific assays of each of the coagulation factors can be performed to determine the nature of the deficiency.
- Samples that are under filled, overfilled or haemolysed give erroneous results and therefore will not be tested.
- Tested at GRH or Oxford Haemophilia Centre.
Sample Requirements
2 x 3ml or 3.5ml Trisodium Citrate tubes x 2
Sample Suitability
Patients should not be on any form of anticoagulation at the time of testing. Sample stability at room temperature in 6 hours post venesection. All samples are centrifuged, aliquoted into LP4 tubes and frozen within this time period.
Turnaround Time
Urgent Factor VIII levels: within 4 hours
Routine: within 2 weeks
Please contact the laboratory in the first instance if urgent factor assays are required, especially outside of routine hours where the test will not be performed unless discussed directly with the laboratory. We aim to process urgent requests within 4 hours.
Reference Ranges
| Test | Range | Notes |
|---|---|---|
| Factor II | 50 - 150% | Tested at Oxford Haemophilia Centre |
| Factor V | 50 - 150% | Tested at Oxford Haemophilia Centre |
| Factor VII | 50 - 129% | |
| Factor VIII | 50 - 150% | |
| Chromogenic Factor VIII | 0.5-2.0 iu/ml | Tested at Oxford Haemophilia Centre |
| Factor IX | 65 - 150% | |
| Factor X | 50 - 150% | Tested at Oxford Haemophilia Centre |
| Factor XI | 65 - 150% | |
| Factor XII | 50 - 150% | |
| Factor XIII | 0.7-1.4 iu/ml | Tested at Oxford Haemophilia Centre |
Interfering substances
Anticoagulation therapy, haemolysed and lipaemic samples.
Add ons
No add on requests accepted for factor assays. Fresh samples are required.
Updated: 15/08/2024