A nurse practitioner (NP) is a registered nurse who has earned a graduate degree and has received advanced academic and clinical experience, which enables him or her to diagnose and manage acute and chronic diseases, illnesses, and conditions. A nurse practitioner can prescribe medication, order diagnostic tests and practice independently, depending on their state of license. A registered nurse is recommended to have extensive clinical experience before applying to a graduate school nurse practitioner program. An intensive preceptorship under the direct supervision of a physician or an experienced nurse practitioner, as well as didactic instruction, are key components to nurse practitioner programs. After completion of their Nurse Practitioner program, they then must pass a licensing exam to become Board Certificated in their area of specialization in order to see patients in their licensing state. To retain their board certification they must recertify, either by examination or through continuing education, every 5 years.