What is the difference between a nurse practitioner and a staff nurse?

According to the American Academy of Nurse Practitioners (AANP), nurse practitioners (NPs) are advanced practice nurses who provide high-quality healthcare services similar to those of a doctor. NPs diagnose and treat a range of health problems. Besides clinical care, NPs focus on health promotion, disease prevention, health education and counseling. NPs have graduate, advanced education and clinical training beyond their registered nurse preparation. Most have master鈥檚 degrees and many have doctorates.
Among the many services that NPs provide, they:
鈥?Order, perform and interpret diagnostic tests such as lab work and x-rays
鈥?Diagnose and treat acute and chronic conditions such as diabetes, high blood pressure, infections and injuries
鈥?Prescribe medications and other treatments
鈥?Manage patients' overall care
鈥?Spend time counseling patients
鈥?Help patients learn how their actions affect their health and well-being

An RNP has undertaken an additional course of study and passed a licensing exam to allow him/her to practice providing primary medical care for more routine medical problems and prescribe certain medications under the direct supervision of a licensed M.D.