Factor XI Inhibitor Profile, Comprehensive
Also known as: Bethesda Titer
Use
Confirmation and characterization of factor XI inhibitor
Special Instructions
The patient should not be on anticoagulation therapy. Ensure proper blood-to-anticoagulant ratio by filling the collection tube completely. Immediate mixing by inversion is necessary to ensure proper anticoagulation. When using a butterfly needle, a discard tube is needed. For multiple frozen samples, submit separate specimens.
Limitations
Residual coagulation factor activity can falsely lower Bethesda titer results. Lupus anticoagulants and antithrombotic agents should be ruled out before testing to avoid false positives. Some inhibitors can fully neutralize factors in under two hours, while autoimmune inhibitors with second-order kinetics may be inaccurately measured in this assay.
Methodology
PCR-based
Biomarkers
LOINC Codes
- 14979-9
- 5946-9
- 43734-3
- 30323-0
- 44950-4
- 3226-8
- 3224-3
Result Turnaround Time
3-5 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
Collect citrated plasma by double centrifugation. Use a blue-top tube containing 3.2% buffered sodium citrate. Samples should be mixed gently at least six times after collection. Centrifuge and transfer plasma carefully to avoid platelet disturbance. Use a plastic transfer pipette and a Labcorp PP transpak frozen purple tube with screw cap for transport.
Patient Preparation
Patient should not be anticoagulated. Avoid drawing from an arm with heparin lock or heparinized catheter.
Storage Instructions
Freeze. Stable at room temperature for four hours.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 4 hours |
Other tests from different labs that may be relevant