A Doctor of Medicine, or M.D.
Diagnoses and treats injuries and illnesses. He or she examines patients; takes medical histories; prescribes medications; orders, performs, and interprets diagnostic tests; recommends and designs a plan of treatment, and helps patients stay healthy by counseling them on diet, hygiene, and preventive health care.
A Doctor of Osteopathic Medicine, or D.O.
Has similar training and the same responsibilities as a medical doctor, but an osteopathic physician places additional emphasis on the body's musculoskeletal system, preventive medicine, and holistic patient care.
A Nurse Practitioner, or NP
Is a Registered Nurse with advanced training and skills. An NP’s responsibilities often include performing a physical exam and ordering laboratory tests and procedures; diagnosing, treating, and managing diseases; and performing certain procedures. The health care services an NP can provide are determined by state law; for example, in some states an NP is allowed to write prescriptions.
A Physician Assistant, or PA
Practices medicine under the direction and supervision of physicians and surgeons. A PA is trained to examine patients, diagnose injuries and illnesses, and provide treatment. A PA typically has completed an accredited educational program leading to a master's degree.
A Registered Nurse, or RN
Is a graduate of a nursing program who provides and coordinates patient care, educates patients about various health conditions, and gives advice and support to patients and their families. An RN’s responsibilities include giving patients medicines and treatments, operating and monitoring medical equipment, and helping to perform diagnostic tests and analyze results.