[Initial experience in the diagnosis of thrombophilia due to activated protein C resistance].

The authors describe the first in Russia cases of thrombophilia caused by factor Va resistance to activated protein C. This abnormality was diagnosed in 6 of 25 patients (24%) with recurrent early thrombosis. The diagnosis was conducted according to a modified method implying the addition of protac (activator of protein C) to normal platelet poor plasma (PPP) free of factor V containing 100% of protein C. Protac dose was adjusted to increase the activated partial thromboplastin time (APTT) 2.4-2.8-fold in mixing PPP of the examinee with plasma containing activated protein C. The indices were estimated indicative of insufficient prolongation of APTT in response to activated protein C. Of 6 patients, 2 had apparent and 4 strong resistance to activated protein C. Treatment policy in this variant of thrombophilia is discussed.