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FACTOR 11 ACTIVITY
Number 199
CPT Code 85270
Alias FACTOR XI ACTIVITY, ANTIHEMOPHILIC FACTOR C, PLASMA THROMBOPLASTIN ANTECEDENT (PTA)
Specimen Container Blue Top Citrate
Specimen Type Plasma Citrate
Turn Around Time
Days Performed
Reference Range
Alternate Specimen
Volume 2 mL Plasma
Stability Ambient N/A
Stability Refrigerated N/A
Stability Frozen Preferred
Patient Preparation
Ideally, the patient should not be on anticoagulant therapy. Avoid warfarin (Coumadin) therapy for two weeks prior to the test and heparin, direct Xa, and thrombin inhibitor therapies for about three days prior to testing.
Methodology
Factor XI activity is determined using an aPTT-based one-stage clotting time assay.
Limitations
Direct Xa or thrombin inhibitor therapy may cause factitiously low results.
Rejection Criteria
Severe hemolysis; improper labeling; clotted specimen; specimen diluted with IV fluids; samples thawed in transit; improper sample type; sample out of stability
Additional Instructions
Performing Laboratory Reference Laboratory
TagsFACTOR 11, F11, FX1