Like most other health professions, medical assisting is governed primarily by state law. This is due to the wording of the Tenth Amendment to the United States Constitution:
The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.
Because the power to regulate professions and occupations is not delegated to the United States Congress in Article I of the Constitution, it remains within the sovereign authority of each state. This authority includes establishing education and credentialing prerequisites for the practice of a profession, delineating legal and ethical responsibilities for the professionals, and issuing and enforcing disciplinary standards for breaches of these responsibilities.
Therefore, the legal scope of practice of medical assistants (which is coterminous with the legal authority of licensed health care providers to delegate to medical assistants) is established by state legislation, regulations and policies of state boards that regulate health professionals who delegate to medical assistants, and common law principles arising from court decisions and usual and customary practice. Federal law, however, sometimes impacts medical assisting scope of practice. The meaningful use regulations of the Centers for Medicare & Medicaid Services (CMS) are a current and significant example. Federal statute and CMS rule require a certain percentage of medication/prescription, laboratory, and diagnostic imaging orders to be entered into the computerized provider order entry (CPOE) system by licensed health care professionals or “credentialed medical assistants” in order for a licensed eligible professional to receive incentive payments under the Medicaid Electronic Health Record (EHR) Incentive Program.