Physician Assistants (PAs) play an important role in the medical field. Physician assistants are health care professionals licensed to practice medicine under the supervision of a physician. Physician assistants perform a number of tasks that include: physical examinations of patients, arrange for diagnostic testing and take part in the interpretation of test results, assist with diagnosing and treating medical conditions, writing medical prescriptions, and counseling patients on health care. Basically Physician assistants have the authority to do almost everything a doctor can do.