under the fair debt collection practices act how long after a medical procedure can they attempt to collect a debt?

The FDCPA prohibits a debt collector from collecting a debt that is part the statute of limitations, which is different from state to state, and differs between an oral contract and a written contract; a debt based on a written contract will have a longer life. If the debt is for a medical procedure, I will bet that it is based on a written contract and the life of that debt will probably be about 7-10 years.