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

Table 2

Workup of baseline isolated prolonged aPTT.

	Test	Patient’s value	Reference range
Heparin onboard	Mixing study	aPTT does not correct with normal plasma
	Lupus anticoagulant	Negative	Negative
	Cardiolipin antibodies	Negative	Negative
	Beta-2-glycoprotein I antibodies	Negative	Negative
Postheparin cessation	Activated clotting time (sec)	714	74–137
	Heparin anti-Xa (IU/mL)	<0.10	0.30–0.70
	Mixing study	aPTT corrects with normal plasma
	Factor II activity (%)	92	70–120
	Factor VIII activity (%)	342	60–150
	Factor IX activity (%)	143	60–150
	Factor X activity (%)	63	70–120
	Factor XI activity (%)	84	60–150
	Factor XII activity (%)	<13	60–150