A patient is any recipient of health care service. The patient is the most often ill or injured and in need of treatment by a registered nurse, physiotherapist, physician, physician assistant, psychologist, podiatrist, veterinarian, or other health care providers. An outpatient (or out-patient) is a patient who is hospitalized for less than 24 hours. Even if the patient will not be formally admitted with a note as an outpatient, he/she is still registered, and the provider will usually give a note explaining the reason for the service, procedure, scan, or surgery, which should include the names and titles and IDs of the participating personnel, the patient’s name and date of birth and ID and signature of informed consent, estimated pre- and post- service time for a history and exam (before and after), any anesthesia or medications needed, and estimated time of discharge, any (further) complications absent. Treatment provided in this fashion is called ambulatory care. Sometimes surgery is performed without the need for a formal hospital admission or an overnight stay. This is called outpatient surgery. Outpatient surgery has many benefits, including reducing the amount of medication prescribed and using the physician’s or surgeon’s time more efficiently. More procedures are now being performed in a surgeon’s office, termed office-based surgery, rather than in a hospitalbased operating room. Outpatient surgery is suited best for healthy patients undergoing minor or intermediate procedures (limited urologic, ophthalmologic, or ear, nose, and throat procedures and procedures involving the extremities). An inpatient (or in-patient), on the other hand, is“admitted”to the hospital and stays overnight or for an indeterminate time, usually several days or weeks, though in some extreme cases, such as with coma or persistent vegetative state patients, stay in hospital for years, sometimes until death. Treatment provided in this fashion is called inpatient care. The admission to the hospital involves the production of an admission note. The leaving of the hospital is officially termed discharge, and involves a corresponding discharge note. A day patient (or day-patient) is a patient who is using the full range of service of a hospital or clinic but is not expected to stay over the night. The term was originally used by psychiatric hospitals to call people needing support to make the transition from in-patient to out-patient care. However, the term is now also heavily used for people attending hospitals for day surgery.