A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # |
Factor X Activity, Clotting
Test CodeF10
Quest Code
359
CPT Codes
85260
Preferred Specimen
1 mL platelet-poor plasma collected in a 3.2% sodium citrate (light blue-top) tube
Minimum Volume
0.5 mL
Instructions
Please submit a separate, frozen vial for each special coagulation assay ordered. Draw blood in a light blue-top tube containing 3.2% sodium citrate, mix gently by inverting 3-4 times. Centrifuge 15 minutes at 1500 g within one hour of collection. Using a plastic pipette, remove plasma, taking care to avoid the WBC/platelet buffy layer and place into a plastic vial. Centrifuge a second time and transfer platelet-poor plasma into a new plastic vial(s). Freeze immediately and transport on dry ice.
Transport Temperature
Frozen
Specimen Stability
Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen: 28 days
Refrigerated: Unacceptable
Frozen: 28 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Hemolysis
Methodology
Photometric Clot Detection
Setup Schedule
Tuesday, Thursday, Friday, Sunday Evening Report available: Next Day
Limitations
Expected impact by therapeutic levels (potential interference depends upon drug concentration): Warfarin: decreased, Heparin (UFH or LMWH): no effect (reagent contains heparin neutralizer); Dabigatran or Argatroban (Thrombin Inhibitors): no effect to inhibitor pattern or falsely low; Rivaroxaban or Apixaban (Factor Xa Inhibitors): no effect to inhibitor pattern.
Reference Range
70-150 % normal
Clinical Significance
The Factor X Activity clotting assay provides a quantitative level of Factor X activity. Factor X is essential for normal hemostasis and deficiencies are associated with increased bleeding risk. As a vitamin K- dependent clotting factor, decreased levels are observed with vitamin K antagonists (eg. warfarin therapy) and vitamin K deficiency. Deficiencies may also occur with hepatic dysfunction, disseminated intravascular coagulopathy (DIC), as a result of inhibitor development, amyloidosis, and with certain malignancies. Congenital Factor X deficiency is extremely rare. Anticoagulant interference: If not clinically contraindicated, avoid warfarin therapy for approximately 2 weeks before testing. Because of the possibility of falsely low levels with direct thrombin inhibitors (eg. Argatroban and Dabigatran) and Factor Xa inhibitors (Rivaroxaban, Apixaban, Edoxaban), these drugs should be avoided, if not clinically contraindicated, for approximately 2-3 days before testing.
Performing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly, VA 20153
Last Updated: November 22, 2023