The CWA-APTT has been reported to detect very low levels of FVIII activity in patients with hemophilia A [16], and has proven useful for the differential diagnosis of hemophilia, acquired hemophilia A, lupus anticoagulant (LA), and DIC, as well as monitoring the results of anticoagulant therapy or bypass therapy in patients with FVIII inhibitors [17,18,19,20,21]. The gene discussed is F8; the disease is hemophilia A.