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 XII Activity, Clotting
Message*Take to processing ASAP
Test Code
362
Alias/See Also
LAB310
CPT Codes
85280
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
Please submit a separate, frozen vial for each special coagulation assay ordered. Draw blood in a light blue-top tube containing 3.2% sodium citrate, mix gently by inverting 3-4 times. Centrifuge 15 minutes at 1500 g within one hour 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(s). Freeze immediately and transport on dry ice.
Transport Container
Transport tube
Transport Temperature
Frozen
Specimen Stability
Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen: 28 days
Refrigerated: Unacceptable
Frozen: 28 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Hemolysis • Received thawed
Methodology
Photometric Clot Detection
Setup Schedule
Mon, wed, fri, sat
Report Available
2-6 days
Limitations
Expected impact by therapeutic levels (potential interference depends upon drug concentration): Warfarin: no effect; 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
50-150 % normal
Clinical Significance
The Factor XII Activity clotting assay provides a quantitative level of Factor XII activity. Deficiency of Factor XII is not associated with a bleeding or thrombotic risk. In the absence of a lupus anticoagulant, Factor XII deficiency should be suspected when an isolated prolonged aPTT occurs in a non-bleeding patient. Direct thrombin or factor Xa inhibitors may yield falsely low results and/or inhibitor pattern with testing. If not clinically contraindicated, avoid for approximately 2-3 days before testing. Vitamin K antagonists (eg. warfarin therapy) have no effect on levels.
Performing Laboratory
Quest Diagnostics Nichols Institute-San Juan Capistrano, CA |
33608 Ortega Highway |
San Juan Capistrano, CA 92675-2042 |