Factor II Functional Activity

F2F

331

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

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.

Plastic screw-cap vial

Frozen

Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen: 28 days

Hemolysis

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.

70-150 % normal

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.