Registered nurses (RNs) perform crucial duties of patient care, including recording medical histories and symptoms, operating medical machinery, performing diagnostic tests, and administering treatments and medications. Patients typically have more contact with RNs than with doctors, and so RNs also have an important role in setting the tone of a patient's visit to the hospital or doctor's office. RNs must obtain a high level of competence in the setting in which they work, and must have the ability and desire to help others who are experiencing health problems or who need preventive care.