<p>The nurse practitioner (NP) concept differs most obviously from conventional nursing practice in that the NP sees patients with undifferentiated and undiagnosed health care problems as the first point of contact. This requires the NP to be able to carry out a physical examination, take a medical history and engage in diagnostic reasoning using new skills that, traditionally, had only been practised by doctors. The rapid development of the NP role in the United States was accompanied by the establishment of university based courses to ensure the NP had the necessary knowledge and skills to practice in an autonomous fashion. Although initially based in primary care, NP roles soon began to develop in hospital emergency department (ED) settings and these nurses acquired the title emergency nurse practitioners (ENPs).</p>