Nurse practitioners (NPs) and physician assistants (PAs) are health care providers who are trained to care for patients in much the same way as doctors. They can perform physical examinations, order tests and interpret results, make treatment decisions, and prescribe many drugs. By law, PAs require a doctor's supervision, whereas NPs do not. Many clinics and hospitals hire NPs and PAs to see patients when there are not enough doctors. Nurse practitioners and PAs also see patients with basic needs so that doctors' more limited time can be spent on patients with more complicated illnesses. Research suggests that NPs and PAs in primary care settings provide the same quality of care as doctors. However, these findings may not apply to specialty settings where patients' needs may be more complicated. Some clinics that focus on the care of patients with HIV infection employ NPs and PAs to see some patients. Whether the quality of care provided by NPs and PAs in an HIV clinic setting is similar to that provided by doctors is not known.