Photo-optical clot determination with Factor XII deficient substrate.
Detection of specific coagulation factor XII deficiency
50-150% of normal activity.
* Reference ranges may change over time. Please refer to the original patient report when evaluating results.
Days Test Performed
Monday - Friday, one run per day
Soft Order Code
Factor 12 Assay
Factor XII Assay
Factor XII:C Assay
Factor 12 Activity
Factor 12 Assay
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Offsite Collection Instructions
Collect specimen in a blue top (citrate 3.2%) tube. Mix by inversion. Specimen should arrive at lab within 3 hours of collection; transport at room temperature. Alternatively, centrifuge, aliquot plasma into a plastic vial, and freeze the specimen within 4 hours of collection. Transport frozen specimen on dry ice. Collection of the blood through lines that have been previously flushed with heparin should be avoided. If the blood must be drawn through a VAD (vascular access device), the line should be flushed with 5 mL of saline and the first 5 mL of blood or six dead space volumes of the VAD discarded.
Specimens will be rejected if not properly filled, clotted, grossly hemolyzed, or contaminated with heparin.
Test is not indicated if the patient is receiving heparin or direct thrombin inhibitor anticoagulation therapy.
Full 2.7mL tube or 1mL plasma aliquot
Full 1.8mL tube or 1mL plasma aliquot
Deficiencies have no hemorrhagic consequence. Factor XII may be increased in patients with pre-eclampsia and decreased in patients with liver disease, renal disease, and Rocky Mountain spotted fever. Congenital Factor XII deficiency has been associated with an increased incidence of venous thrombosis.