Case Report

Friend or Foe: Factor XII Deficiency Discovered Incidentally during Management of NSTEMI

Table 2

Workup of baseline isolated prolonged aPTT.

TestPatient’s valueReference range

Heparin onboardMixing studyaPTT does not correct with normal plasma
Lupus anticoagulantNegativeNegative
Cardiolipin antibodiesNegativeNegative
Beta-2-glycoprotein I antibodiesNegativeNegative

Postheparin cessationActivated clotting time (sec)71474–137
Heparin anti-Xa (IU/mL)<0.100.30–0.70
Mixing studyaPTT corrects with normal plasma
Factor II activity (%)9270–120
Factor VIII activity (%)34260–150
Factor IX activity (%)14360–150
Factor X activity (%)6370–120
Factor XI activity (%)8460–150
Factor XII activity (%)<1360–150