Name: Factor Inhibitor Assay
Test Name: Factor Inhibitor Assay
Health Link Test Code: GM1335
LIS Test Code: FIA
CPT Code(s): 85335
Factor Inhibitor assays are available when a specific inhibitor strength needs to be assessed. A factor activity level will be performed prior to the Factor Inhibitor Assay.
Methodology: Bethesda Inhibitor Assay
The assay is used to determine the titer of inhibitor to specific factors.
Days Performed: Mon-Fri, dayshift - day varies. Specimens are accepted at any time. Testing required during off hours must be approved by a Coagulation physician. Call 263-5005 before collection.
In-Lab Turnaround Time: 4 - 10 days.
Stat In-Lab Turnaround Time: 1 day.
Patient MUST be off direct thrombin inhibitor for 24 hours and off heparin for 72 hours prior to blood collection.
Collection Container: Light blue top (3.2% NaCitrate)
Please note factor to be assayed. Do NOT draw through a line containing heparin. The venipuncture MUST be atraumatic to avoid hemolysis and contamination with tissue factors and platelets. Tube must be allowed to fill completely.
Indicate if patient is receiving anticoagulant (warfarin/Heparin/ Vitamin K antagonist), direct thrombin inhibitor or fibrinolytic agent therapy and duration.
Collection Volume: Four full 3.5 mL tubes
Pediatric Collection Volume: 2 full pediatric tubes filled to mark
4 hours on a spun tube
2 weeks at -20°C; 6 months at -70°C
Sample Analyzed: Plasma
Testing Volume: 5 mL
Pediatric Testing Volume: 1.5 mL
Ultracentrifuge sample and label "ULT". If an ultracentrifuge is not available, centrifuge tube to obtain platelet poor plasma (platelet count should be 10 K/µL or less). Separate plasma from cells and transfer to plastic tube and spin again. Transfer this plasma to clean plastic tube or vial. Indicate on tube "spun twice". Freeze plasma within 4 hours of collection at -20°C or below.
Transport whole blood specimen at room temperature to UWHC Hospital Laboratory within 4 hours of collection. See "Specimen Processing" for instructions if transport criteria can not be met. Transport frozen plasma aliquot on dry ice to UWHC Hospital Laboratory.
Hemolyzed specimens, clotted specimens, partially filled tubes and whole blood specimens greater than 4 hours old when received by the laboratory are not acceptable.
Age 1 year and up: Negative
Interpretation Type: Expected Results