Factor IX Inhibitor
Also known as: Bethesda Titer
Use
Confirmation and characterization of factor IX inhibitor
Special Instructions
Factor IX inhibitors arise as alloantibodies in a minority of hemophilia B patients and can affect treatment efficacy. Coagulation samples should be collected and processed with care to avoid false results due to residual coagulation factor activity or lupus anticoagulant interference. Separate frozen specimens are recommended if multiple tests are requested.
Limitations
The presence of residual coagulation factor activity can falsely lower the Bethesda titer result. Lupus anticoagulant activity and antithrombotic agents should be ruled out to avoid factitiously positive results. Inhibitors with rapid kinetics may neutralize factors sooner than detectable in this test. Autoimmune inhibitors with complex kinetics are difficult to measure accurately.
Methodology
Other
Biomarkers
LOINC Codes
- 3187-2
- 3185-6
Result Turnaround Time
2-5 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
4 mL (2 mL in each of two tubes)
Minimum Volume
Not provided
Container
Blue-top (sodium citrate) tubes
Collection Instructions
Citrated plasma samples should be collected by double centrifugation. Blood should be collected in a blue-top tube containing 3.2% buffered sodium citrate. The sample should be mixed immediately by gentle inversion at least six times. Freeze immediately and maintain frozen until tested.
Patient Preparation
The patient should not be anticoagulated. Do not draw from an arm with a heparin lock or heparinized catheter.
Storage Instructions
Freeze.