Factor 12 activity

Alphabetical Test listing

Factor 12 activity-994

Factor 12 activity
Factor XII activity
Hageman factor
Surface factor

Evaluate a prolonged aPTT and detect specific coagulation factor XII activity

Sodium citrate (Na cit) plasma
1.0 mL
1.0 mL
  • Collection tubes must be filled to completion to ensure a proper blood-to- anticoagulant ratio.
  • If the patient's hematocrit exceeds 55%, the volume of citrate in the collection tube must be adjusted.
  • The sample should be mixed immediately by gentle inversion at least six times to ensure adequate mixing of the anticoagulant with the blood.
  1. Spin
  2. Transfer plasma to a Screw-cap polypropylene frozen transport vial/tube - 4mL (LabCorp), labelled as Na cit plasma
  3. Freeze




Frozen - 14 days

  • Freeze/thaw cycles - stable x3
  • Severe hemolysis
  • Improper labeling
  • Clotted specimen
  • Specimen diluted with I.V. fluids
  • Samples thawed in transit
  • Improper sample type
  • Sample out of stability
LabCorp Burlington (086322): R-NX
Tu - Fr
2 - 3 days

aPTT-based one-stage clotting time assay. Factor XII-depleted plasma is used as the substrate and the clotting time with the patient plasma is compared to the clotting time of normal pooled plasma.


50 - 150%

Result 3232-6