Leaches = test ?
When the doc applies them, both he and the other guy seem ready to strike (one with a gun, the other with a blade). But then they seem to relax when the leaches take hold. So we are lead to believe that if they had not taken to her leg, she would have been diagnosed as a lycan and killed.
EDIT : actually, the "positive" test means the leach turns into some sort of super-leach.
Has anyone ever heard of leaches being a test in other films : books ?
Smiling is for the weak.