Triage () is the process of determining the priority of patients' treatments based on the severity of their condition. This rations patient treatment efficiently when resources are insufficient for all to be treated immediately. The term comes from the French verb trier, meaning to separate, sift or select. Triage may result in determining the order and priority of emergency treatment, the order and priority of emergency transport, or the transport destination for the patient. Triage may also be used for patients arriving at the emergency department, or telephoning medical advice systems, among others. This article deals with the concept of triage as it occurs in medical emergencies, including the prehospital setting, disasters, and emergency department treatment. The term triage may have originated during the Napoleonic Wars from the work of Dominique Jean Larrey. The term was used further during World War I by French doctors treating the battlefield wounded at the aid stations behind the front. Those responsible for the removal of the wounded from a battlefield or their care afterwards would divide the victims into three categories: Those who are likely to live, regardless of what care they receive; Those who are unlikely to live, regardless of what care they receive; Those for whom immediate care might make a positive difference in outcome.For many emergency medical services (EMS) systems, a similar model may sometimes still be applied. In the earliest stages of an incident, such as when one or two paramedics exist to twenty or more patients, practicality demands that the above, more "primitive" model will be used. However once a full response has occurred and many hands are available, paramedics will usually use the model included in their service policy and standing orders. As medical technology has advanced, so have modern approaches to triage, which are increasingly based on scientific models. The categorizations of the victims are frequently the result of triage scores based on specific physiological assessment findings. Some models, such as the START model may be algorithm-based. As triage concepts become more sophisticated, triage guidance is also evolving into both software and hardware decision support products for use by caregivers in both hospitals and the field.