Test Code: F11 Preferred Name Factor XI

2 hours
1 week
Medicare Item
2 hours

Test Tubes

ImageSpecimen TypeSpecimen VolumeTube Type
Blood (adult)2.7 mLSodium Citrate 2.7 mL (Solid Pale Blue Top)
Blood (paediatric)1.8 mLSodium Citrate 1.8 mL Paed (Clear/Pale Blue Inner)
Blood (neonate)1.0 mLSodium Citrate 1.0 mL Neonate (Pale Blue Top)


Accurate filling of specimen tube essential.
Specimens must be transported at room temperature to the Laboratory in a red specimen bag ASAP. (Maximum delay to testing laboratory must not exceed 2hrs)
* If several factor assays are requested, e.g. VIII, IX, XI, and XII, 3 x sodium citrate tubes are required for an adult and 2 tubes for a child.


Factor XI has a biological half-life of 80 hours. Thrombin generation is never as impeded in F XI deficiency as it is in the other factor deficiencies. Deficient individuals may experience increased bleeding after aspirin ingestion, prostatectomy, and oral cavity surgery and when there is increased fibrinolytic activity. Acquired F XI inhibitors may be seen in patients with SLE.

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