|
|
| 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 XI Activity and Human Inhibitor
Test Code17854
CPT Codes
85270, 85335
Preferred Specimen
2 mL frozen platelet-poor plasma collected in (x2) 3.2% sodium citrate (light blue-top) tubes
Minimum Volume
1 mL (x2)
Instructions
Platelet poor plasma: Centrifuge light blue-top tube for 15 minutes at approximately 1500 x 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. Do not thaw.
Transport Container
Plastic screw-cap vials
Transport Temperature
Frozen
Specimen Stability
Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen -20°C: 14 days
Frozen -70°C: 1 year
Refrigerated: Unacceptable
Frozen -20°C: 14 days
Frozen -70°C: 1 year
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Hemolyzed specimens
Methodology
Clot based, Bethesda Assay
Setup Schedule
Set up: Tues; Report available: 3 days
Reference Range
| Factor XI Activity | 65-150 | %normal |
| Factor XI Human Inhibitor | <0.4 | Bethesda unit |
Clinical Significance
Factor XI Inactivator assay issued to quantitate inhibitor present in patient sample. The Bethesda assay is the most common test for determination of circulating FXI inhibitor in plasma.
