Physician assistants (PAs) provide healthcare services under the supervision of physicians. PAs are formally trained to provide diagnostic, therapeutic, and preventive healthcare services, as delegated by a physician. Working as members of the healthcare team, they take medical histories, examine and treat patients, order and interpret laboratory tests and X-rays, make diagnoses, and prescribe medications. They also treat minor injuries by suturing, splinting, and casting. PA's record notes, instruct and counsel patients, and order or carry out therapy. PAs may be the principal care providers in rural or inner city clinics, where a physician is present for only 1 or 2 days each week. In such cases, the PA confers with the supervising physician and other medical professionals as needed or as required by law. PAs also may make house calls or go to hospitals and nursing homes to check on patients and report back to the physician. They are trained to function in a variety of settings such as private offices, clinics, hospitals, emergency departments, health maintenance organizations, neighborhood health centers, armed services, and federal and state agencies.