Test Overview
Photo-optical clot determination with Factor XI deficient substrate.
Detection of specific coagulation factor XI deficiency
50-150% of normal activity.
* Reference ranges may change over time. Please refer to the original patient report when evaluating results.
Test Details
2 hours
- Factor 11 Activity
- Factor XI Assay
- Factor XI:C Assay
- F11
- Factor 11 Assay
STAT requests for this request will be performed for UMHS inpatients, Emergency Department patients, and Veterans Hospital patients.
Specimen Requirements
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 polypropylene 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.
Additional Information
Factor XI normally increases during pregnancy. Decreased factor XI may be associated with: factor XI deficiency, nephrotic syndrome, pre-eclampsia, and Noonan's syndrome.