Sign in →

Test Code FAXCHR Chromogenic Factor X Assay

Specimen and Container/Tube

Specimen Type: Plasma

Preferred Specimen: Light Blue Top Tube, 3.2% Sodium Citrate

Other Acceptable specimens: N/A

Specimen Handling and Transport Instructions

UCMC Onsite Instructions: 

Collect specimen per standard collection procedure and send to laboratory immediately. 

 

NOTE: Once each blue top tube is completely filled, gently invert the sample tube at least five times to ensure complete mixing of the contents.

 

UCMC Offsite and UC MedLab Outreach Instructions: 

  • Collect specimen per standard collection procedure.
  • Once each blue top tube is completely filled, gently invert the sample tube at least five times to ensure complete mixing of the contents.
  • Centrifuge specimens at >2500 x g for 10 minutes at room temperature.
  • Carefully remove plasma from cells using a plastic transfer pipette avoiding buffy coat.
  • Aliquot removed plasma into 2 plastic tubes containing a minimum of 1.0 mL of specimen in each tube.
  • Plasma samples must then be frozen at -20oC.
  • Once solidly frozen, they must be shipped on dry ice. Samples that have thawed in transit will be rejected.

Rejection Criteria

  • Common specimen rejected situations include: incorrect specimen type, insufficient volume, missing or incomplete specimen identifiers, incorrect specimen transport, or specimens outside stability limits. 
  • Specimens that have wrong ratio of blood to anticoagulant (fill volume), clotted or grossly hemolyzed.

Reference Values

 

Test

Age

Sex

Reference Range

Factor X Chromogenic

All

All

74 - 124%

Critical Values

Analyte

Unit

Low

High

Age

N/A

N/A

N/A

N/A

N/A

CPT Codes

85130 

LOINC Codes

3219-3

Volume

Preferred Volume: 2.0 mL

 

Minimum Volume: 1.0 mL

Specimen Stability

Storage Temperature

Stability

Room temperature

4 hours

Refrigerated

not acceptable

Frozen

30 days

Collection Instructions

Collect specimen per standard laboratory collection procedures. 

 

NOTE: Once each blue top tube is completely filled, gently invert the sample tube at least five times to ensure complete mixing of the contents.

 

Turnaround Time

Turnaround times are relative to the time the specimen is received in the test laboratory. 

STAT Turnaround Time: N/A

 

Routine Turnaround Time: Up to 3 days

 

Testing Schedule: Monday to Friday from 8:00 am to 3:30 pm.

Clinical Indications

May be helpful as a monitor of oral anticoagulant therapy in instances where the INR is not reliable (e.g., cases where a
Lupus Anticoagulant has significantly prolonged the baseline PT/INR or if the patient is being bridged from a direct thrombin inhibitor onto warfarin).

Methodology

Chromogenic

Synonyms/Keyword Search

Factor X 

Additional Information

Although the relationship is not precise between the INR and the chromogenic factor X level (r-squared=0.422), in 50 patients receiving oral anticoagulant therapy and having a chromogenic factor X level between 15-35%, all were found to have an INR between 2.0-4.0. McGlasson et al showed that in 339 warfarinized patients with a reliable INR, a therapeutic INR of 2.0 to 3.0 corresponded to a chromogenic X level of 35.5% to 23.5%, respectively. Blood Coagulation and Fibrinolysis. 2008. 19:513–517

Last Review Date

03/13/2024