Can they do a tox screen as part of their emergency care? Yes.
If a person has illegal drugs on their person at the E.R., the illegal drugs may be turned over to the police. Their discovery by E.R. personnel doesn't make them any less illegal, even if the police weren't present when they were found. If the minor believes he can make the case that the drugs were planted by the E.R. personnel, he's free to try.

