The main distinction between the two disciplines is that the practice of physician assistants is specifically under the direction and supervision of a physician and is regulated by the state's Medical Practice Act, whereas the practice of nurse practitioners is governed by the Nurse Practice Act. Nurse practitioners have sought more independence in their practice relationships and legislation allowing greater prescriptive authority and direct reimbursement for their services. The legal scope of practice for midlevel practitioners varies from state to state. In 34 states nurse practitioners are allowed to practice independently without specific physician supervision. In 46 states nurse practitioners have prescriptive authority with different degrees of autonomy.
Reimbursement varies depending on the payer, site, and type of service and state.
The quality and outcome of care provided by midlevel health practitioners appears to be comparable to that provided by physicians within well-defined clinical settings. Surveys show that patients are consistently satisfied with care they receive from midlevel practitioners. A meta-analysis of 38 studies published by the American Nursing Association concluded that care provided by nurse practitioners is equal to or superior to that provided by primary care physicians. However, the analysis has been criticized because most of the relevant literature is more than 20 years old and contains serious methodologic flaws, including no adjustment for case mix or severity of disease. Furthermore, all the studies involved collaborative practices with physicians.