Most of us are familiar with MD after a doctor's name. This stands for doctor of medicine and signifies that this person has completed four years of medical school. But would you know if your doctor is a DO? And what about the other people checking vitals, writing prescriptions, and filling in charts—PAs and NPs—what type of training do they have and what services can they offer?

MDs and DOs

A DO is a doctor of osteopathic medicine. MDs and DOs are similar in many ways. Here are some requirements that both MDs and DOs must complete:

• Complete four years of medical school
• Complete residency programs, which involves 3-8 years of additional training
• Pass state licensing exams (obtain licenses to prescribe medicine and perform procedures)
• Practice in accredited hospitals and medical centers
• Earn continuing education units to remain certified

There are also some distinctions between these types of doctors. For example, DOs:

• Use a technique called osteopathic manipulative treatment (OMT). With OMT, DOs use their hands to manage their patient’s injuries and illnesses.
• Receive extra training in the musculoskeletal system. This system consists of interconnected muscles, tendons, ligaments, and bones. DOs are trained in a philosophy of medicine that places great emphasis on the importance of this system to the maintenance and restoration of health.
• Focus on primary care medicine. The majority of DOs practice in areas of primary care, such as pediatrics, family practice, obstetrics/gynecology, and internal medicine.
• Are trained to spend more time considering the broad range of factors affecting health. (MDs may also have this holistic approach.)
• Focus on preventive health care.

Physician Assistants

A physician assistant (PA) is a health professional who is licensed to practice medicine under the supervision of a physician. Some of the duties that a PA can do include:

• Obtain a medical history and perform a physical exam
• Diagnose and treat illnesses and minor injuries
• Order and interpret tests (such as lab work and x-rays)
• Counsel on preventive health and lifestyle practices
• Assist in surgery
• Prescribe medicines

A PA can work in any area of medicine, but the majority work in primary care medicine (pediatrics, family practice, obstetrics/gynecology, and internal medicine).

To become a PA, a person must complete an accredited PA educational program and pass a national certification exam. The typical PA program takes about two years. The majority of students have a bachelor's degree and experience in the healthcare field before admission to the program. Education consists of classroom and laboratory instruction in the basic medical and behavioral sciences, as well as clinical rotations in different medical fields. Once certified, PAs take continuing medical education classes and are regularly retested on their skills.

Nurse Practitioners

A nurse practitioner (NP) is a registered nurse (RN) with a master's degree in nursing and clinical training in a healthcare specialty area. The services a NP can provide vary depending on each state's regulations. In general, NPs can:

• Obtain a medical history and perform a physical exam
• Diagnose, treat, and monitor illnesses and injuries
• Order and interpret tests (eg, lab work and x-rays)
• Prescribe medicines (in most states)
• Counsel on preventive health and lifestyle practices

Nurse practitioners can work in primary care (pediatrics, family practice, obstetrics/gynecology, and internal medicine) or specialty areas of medicine, such as emergency medicine, oncology, and psychiatry.

The path to becoming a NP usually begins with nursing school, followed by licensure as an RN. After a few years of work experience, an RN can apply to a master's degree program in nursing (generally 1-2 years of school and a supervised internship). Most NPs are nationally certified in their specialty area.

Knowing When to Say When

While PAs and NPs can do many of a doctor's functions, an essential part of their training is knowing when to defer to a doctor. Exactly what a PA or NP can handle and what they pass onto the doctor varies greatly with training, experience, state law, and the supervising doctor's practice. Generally, a doctor handles patients with medical issues that are outside of the range of the assistant or nurse.