The practice of medicine includes taking a complete medica history, doing a full examination of a patient, establishing a differential diagnosis, ordering tests to help  define a more limited differential diagnosis or arrive at a final diagnosis proposing a treatment plan including prescriptions for medications and ancillary care (such as physical therapy, psychotherapy, rehabilitation care, etc.), following up on the treatment plan to modify any recommendations and follow the course of the disease and its response to treatment.

FSMB (Fed of State Med Boards)

State Medical Practice Acts define what constitutes the practice of medicine in that State. Generally, the definition of the practice of medicine is consistent among the States though particular details do vary from State to State. Additionally, other healthcare regulatory Boards may have similar language in their own definitions of practice. The Federation of State Medical Boards defines the practice of medicine in the Essentials of a Modern Medical Practice Act as: 

• advertising, holding out to the public or representing in any manner that one is authorized to practice medicine in the jurisdiction; 

• offering or undertaking to prescribe, order, give or administer any drug or medicine for the use of any other person; 

• offering or undertaking to prevent or to diagnose, correct and/or treat in any manner or by any means, methods, or devices any disease, illness, pain, wound, fracture, infirmity, defect or abnormal physical or mental condition of any person, including the management of pregnancy and parturition; 

• offering or undertaking to perform any surgical operation upon any person; 

• rendering a written or otherwise documented medical opinion concerning the diagnosis or treatment of a patient or the actual rendering of treatment to a patient within a State by a physician located outside the State as a result of transmission of individual patient data by electronic or other means from within a State to such physician or his or her agent; 

• rendering a determination of medical necessity or a decision affecting the diagnosis and/or treatment of a patient; and 

• using the designation Doctor, Doctor of Medicine, Doctor of Osteopathy, Physician, Surgeon, Physician and Surgeon, Dr., M.D., D.O. or any combination thereof in the conduct of any occupation or profession pertaining to the prevention, diagnosis or treatment of human disease or condition unless such a designation additionally contains the description of another branch of the healing arts for which one holds a valid license in the jurisdiction.