Factor XII Inhibitor Profile, Comprehensive
Also known as: Bethesda Titer
Use
Confirmation and characterization of factor XII inhibitor
Special Instructions
A proper draw volume is crucial for accurate testing; ensure tubes are filled to completion. Use the Labcorp PP transpak frozen purple tube with a screw cap for plasma transport, and maintain the sample frozen until tested. It is also important to rule out lupus anticoagulant activity, as it can cause false-positive results.
Limitations
Residual coagulation factor in the plasma may lead to falsely lowered results. Lupus anticoagulant activity must be excluded prior to testing for factor inhibitors. The presence of direct Xa and thrombin inhibitor anticoagulants can cause false-positive results. Some inhibitors may completely neutralize factors in less than two hours, impacting the assay results. Autoimmune inhibitors cannot be accurately evaluated with the Bethesda titer system due to their kinetics.
Methodology
Immunoassay (Other)
Biomarkers
LOINC Codes
- 14979-9
- 14979-9
- 5946-9
- 43734-3
- 30323-0
- 44950-4
- 3232-6
- 3230-0
Result Turnaround Time
3-7 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
6 mL (2 mL in each of three tubes)
Minimum Volume
Not provided
Container
Blue-top (sodium citrate) tubes
Collection Instructions
Citrated plasma samples should be collected by double centrifugation. Collect blood in a blue-top tube containing 3.2% buffered sodium citrate. Fill tubes to ensure proper blood to anticoagulant ratio. Mix immediately by gentle inversion six times. No discard tube needed unless using a winged blood collection device. Double centrifuge and transfer plasma to a Labcorp PP transpak frozen purple tube. Freeze immediately.
Patient Preparation
Ensure the patient is not anticoagulated. Avoid drawing from an arm with a heparin lock or heparinized catheter.
Storage Instructions
Freeze. Stable at room temperature for four hours.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 4 hours |