Because hypercoagulability expresses itself in the short interval between the normal clotting time and the minimal clotting time and shortening of the PT is very sensitive to hypocoagulation but relatively insensitive to hypercoagulation, we defined the transformation of prothrombin time (PT-t) as the inverse of the difference between PT in patients and the minimal PT of normal plasma for further analysis. The gene discussed is F2; the disease is thrombophilia.