Factor II Activity, Clotting

Test Code

CPT Codes

Preferred Specimen
1 mL platelet-poor plasma collected in a 3.2% sodium citrate (light blue-top) tube

Minimum Volume
0.5 mL

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 Container
Plastic screw-cap vial

Transport Temperature

Specimen Stability
Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen: 28 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Photometric Clot Detection

Setup Schedule
Set up: Sun, Tues, Thurs, Fri; Report available: 1-4 days

Expected impact by therapeutic levels (potential interference depends upon drug concentration): Warfarin: decreased, Factor V-no effect; 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
Factor II Activity, Clotting - The Factor II Activity clotting assay provides a quantitative level of Factor II (also known as Prothrombin) activity. Factor II/Prothrombin 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 or as a result of inhibitor development. Antibodies to prothrombin can occur in patients with anti- phospholipid antibodies and can cause significant clinical bleeding; however, because these antibodies bind to a nonactive portion of the molecule, increased clearance occurs, so that a deficiency rather than an inhibitor is detected. Congenital Factor II deficiency is extremely rare. Anticoagulant interference: if not clinically contraindicated, avoid warfarin therapy for approximately 2 weeks before testing. Direct Xa or thrombin inhibitor therapy may cause falsely low levels (avoid for approximately 2-3 days before testing if not clinically contraindicated.

The Factor II Activity, Clotting assay IS NOT intended to identify the Prothrombin 20210G>A Gene Mutation, which is associated with the increased thrombotic risk.

Performing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly, VA 20153

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.