Been carrying in PA for maybe 20 years.
My local chief has told me that the only places you can't carry are federal court houses, airports and post offices.......if you carry anyplace else that has a posted NO GUNS sign, all they can do is ask you to leave should they become aware you have one. I even asked him about carrying in bars because there is some Liquor control board clause (state liquor lisc. agency).......he said you can carry in a bar.
On a side note, the pittsburgh arena has had a no weapons policy sign for many years and I blatantly ignore it.........after 911, they put security at all the doors and check under your jacket as you go in.......hehe....shame they don't check your pockets..........but anyway..to answer your question......yes...you can carry in a hospital......even if they have a sign saying you can't.