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Factor IX Activity, Clotting [352X]
Test CodeF9
Quest Code
29133
Alias/See Also
Factor IX
F9 Activity
F9 Activity
CPT Codes
85250
Preferred Specimen
1 mL frozen platelet-poor plasma collected in a 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, take 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 Container
Plastic screw-cap vial
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
Set up: Mon-Fri; Report available: Next day
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.
Reference Range
60-160% normal
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.
Performing Laboratory
Quest Diagnostics Nichols Institute |
14225 Newbrook Drive |
Chantilly, VA 20153 |
Last Updated: September 11, 2019