Medical care is regulated on the state level at the moment of the United States' formation.
Date: 1776
Following colonial practices, each state has the right to determine how to regulate medical practices, including the system of licensure for doctors. This means that moving from one state to another is expensive for physicians, as they have to pay for additional licensing, and, sometimes, additional training to meet each state's requirements.
Less regulation also means greater freedom for physicians to practice medicine in their own ways because there are no defined national medical standards. However, some physicians will take advantage of this freedom, using charm and fake medicine to make money off of isolated rural people.