She became a normal human the day Misha pushed her against the glass unit & she was bleeding badly, then Abhay, remember he said to an unconcious Piya that "after today you will become a normal human if I am able to save you"..
but u know that chand, hasina and abhay were saying that piya blood is still a vampire blood so she cannot be checked by doctors😕...their r lots of confusion in the show...