Differentiating between a physician assistant (PA) and a nurse can be a bit difficult, particularly because there are many different types of nurses. Licensed vocational nurses (LVNs), registered nurses (RNs), and nurse practitioners (NPs) are just three types of nurses all with different educational requirements, licensure guidelines, and job responsibilities. At a very basic level, the difference between a PA and a nurse is this: a physician assistant is trained to diagnose and treat medical illnesses, albeit under the supervision of a physician, while a nurse primarily provides nursing, or bedside, care. A PA therefore generally has more decision making autonomy in a patient's care, than a nurse does.

Nurse Practitioners, however, have an advanced level of education, training, and experience and therefore can have a wider scope of practice than other nurses and PAs. NPs provide both medical and nursing care.

A physician assistant is a licensed health care professional, who's scope of practice is determined by his or her training, experience, and state laws. A PA can generally provide about 75% of the services that a physician can provide but a PA must work under the supervision of a physician. Working under the supervision of a physician does not require that the physician be physically present at all stages of a patient's care. It is possible for a PA to act as the primary care provider in clinics where the physician is only occasionally present. This practice is most common in inner city and rural clinics where the number of physicians is low compared to the patient population. A physician assistant may also make house calls or travel to hospitals and other facilities in order to check on patients and report their progress to the physician.

Like physicians, PAs generally do not perform clerical tasks, as a nurse may sometimes provide. Generally, more complex cases are handled by a physician rather than a PA.

While a physician assistant may diagnose a patient, most nurses, with the exception of nurse practitioners, cannot. Rather, a nurse cares for the patient by following the physician’s orders and reporting any changes in the patient’s physical or emotional health to the physician. Nurse practitioners, however, may operate independently and therefore have even greater autonomy than a physician assistant.

Like a nurse, a physician assistant is a part of the health care team. He or she may examine the patient, as well as take a medical history, provide treatment, order and interpret laboratory tests and x-rays, and diagnose illnesses. A physician assistant may also treat certain injuries, such as those requiring splinting, suturing, and casting. In most of the United States, a physician assistant is also permitted to prescribe medications. Some states permit nurse practitioners to write prescriptions.

In order to become a physician assistant, one must complete a physician assistant program and pass a national exam. Most of these PA programs are two year programs. Unlike physicians, PAs do not have to complete internships or residencies. Nurses also have specific educational requirements they must meet, with nurse practitioners having the most amount of education required, namely a masters degree. Once licensed, a physician assistant generally has the potential to earn a higher annual salary than a nurse.