Coagulation Factor X Chromogenic Activity Assay, Plasma
Use
Monitoring warfarin anticoagulant therapy, especially in patients with lupus anticoagulants that interfere with baseline prothrombin time/international normalized ratio and in patients on argatroban transitioning to warfarin. The chromogenic factor X activity assay serves as an alternative to the INR for monitoring warfarin therapy, unaffected by LAC as the end-point is not a phospholipid-dependent clotting time.
Special Instructions
If factor X deficiency is suspected, order F_10 / Coagulation Factor X Activity Assay, Plasma. For accurate results, use a double-centrifuged specimen to avoid platelet contamination. Fasting for 8 hours is preferred but not required prior to specimen collection.
Limitations
This assay should not be used for monitoring heparin or oral direct factor Xa inhibitors like rivaroxaban, apixaban, or edoxaban. Liver disease and vitamin K deficiency may lower factor X levels, potentially impacting results.
New York Approved
Methodology
Chromogenic
Biomarkers
LOINC Codes
- 33984-6
- 33984-6
Result Turnaround Time
1-3 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
1 mL
Minimum Volume
0.5 mL
Container
Light-blue top (citrate); Submission: Polypropylene plastic vial
Collection Instructions
Centrifuge, transfer all plasma into a plastic vial, and centrifuge plasma again. Aliquot into a new vial, leaving 0.25 mL. Freeze immediately at -20 to -40°C.
Patient Preparation
Fasting for 8 hours is preferred but not required.
Causes for Rejection
Gross hemolysis, lipemia, or icterus
Stability Requirements
| Temperature | Period |
|---|---|
| Frozen | 14 days |