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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 IX Activity, Clotting (352X)
Test CodeFIX
Preferred Specimen
1 mL frozen platelet-poor plasma collected in 3.2% sodium citrate (light blue-top) tube
Minimum Volume
0.5 mL
Instructions
Centrifuge light blue-top tube for 15 minutes at approximately 1500 g within 60 minutes 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. Plasma must be free of platelets (<10,000/mcL). Freeze immediately and ship on dry ice.
Transport Temperature
Frozen
Specimen Stability
Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen: 14 days
Refrigerated: Unacceptable
Frozen: 14 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Hemolysis • Received thawed
Methodology
Photometric Clot Detection
Setup Schedule
Sets up 3 days a week.
Report Available
Reports in 3-6 days.
Limitations
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.
Clinical Significance
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.
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.