Factor IX Activity 352X

FAC 9

FAC 9

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

1

Draw light blue (sodium citrate and send platelet-poor plasma frozen with 30 min of drawing specimen

BLUE

F

Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen: 14 days

Hemolysis • Received thawed

Set up: Mon-Fri; Report available: Next day

Expected impact by therapeutic levels (potential interference depends upon drug concentration): Warfarin: Decrease; Heparin (UFH or LMWH): no effect to inhibitor pattern; Dabigatran or Argatroban (Thrombin Inhibitors): no effect to inhibitor pattern; Rivaroxaban or Apixaban (Factor Xa Inhibitors): no effect to inhibitor pattern.

60-160% normal

This test is useful to evaluate a prolonged aPTT. Deficiency of Factor IX can be seen with congenital deficiency (Hemophilia B, X-linked disorder) which affects approximately 1 in 25,000 males. As a vitamin K-dependent clotting factor, decreased levels are also observed with vitamin K antagonists (eg. warfarin therapy) and vitamin K deficiency. Deficiencies may be seen with liver disease, disseminated intravascular coagulation (DIC) and in other consumptive coagulopathies.

Anticoagulant interference: Expected impact by therapeutic levels (potential interference depends upon drug concentration): Warfarin: decrease; Heparin (UFH or LMWH): no effect to inhibitor pattern; Dabigatran or Argatroban (Thrombin Inhibitors): no effect to inhibitor pattern; Rivaroxaban, Apixaban, Edoxaban (Factor Xa Inhibitors): no effect to inhibitor pattern. Other limitations: Lupus anticoagulant may cause falsely low to inhibitor pattern. Factor specific inhibitors (autoantibodies or in response to replacement therapies) may cause falsely low or inhibitor patterns.