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HelpTest Code FXCH Coagulation Factor X Chromogenic Activity Assay, Plasma
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Reporting Name
Factor X Chromogenic Activity AssaySpecimen Type
Plasma Na CitSpecimen Required
Patient Preparation: Fasting preferred
Collection Container/Tube: Light-blue top (citrate)
Submission Container/Tube: Polypropylene vial
Specimen Volume: 1 mL
Collection Instructions:
1. For complete instructions see Coagulation Guidelines for Specimen Handling and Processing
2. Spin down, remove plasma, and spin plasma again.
3. Freeze plasma immediately (no longer than 4 hours after collection) at -20° C or, ideally, at or below -40° C.
Additional Information:
1. Double-centrifuged specimen is critical for accurate results as platelet contamination may cause spurious results.
2. Each coagulation assay requested should have its own vial.
3. If priority specimen, mark request form, give reason, and request a call-back.
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
| Gross icterus | Reject |
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Plasma Na Cit | Frozen | 14 days |
Specimen Minimum Volume
0.5 mL
Special Instructions
Day(s) Performed
Monday through Friday
Specimen Retention Time
7 daysReport Available
1 to 3 daysReference Values
≥18 years of age: 60%-140%
Chromogenic Factor X activity generally correlates with the one-stage factor X activity. In full term or premature neonates, infants, and children, the one-stage factor X activity* is lower than adult reference range and progressively rises to the adult reference range by adolescence. However, no similar data for the chromogenic factor X activity have been published.
*See Pediatric Hemostasis References section in Coagulation Guidelines for Specimen Handling and Processing.
Useful For
Monitoring warfarin anticoagulant therapy, especially in patients whose plasma contains lupus anticoagulants that interfere with baseline prothrombin time/international normalized ratio and in patients receiving the drug Argatroban who are being transitioned to warfarin
This assay should not be used for monitoring heparin, or oral direct factor Xa inhibitors such as rivaroxaban (Xarelto), apixaban (Eliquis), or edoxaban (Savaysa).
CPT Code Information
85260
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| FXCH | Factor X Chromogenic Activity Assay | 33984-6 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| FXCH | Factor X Chromogenic Activity Assay | 33984-6 |
Forms
If not ordering electronically, complete, print, and send a Coagulation Test Request (T753) with the specimen.