Key concepts

Mental health-related services in emergency departments
Key concept Description

Emergency department (ED) presentation

Emergency department (ED) presentation refers to the period of treatment or care between when a patient presents at an emergency department and when that person is recorded as having physically departed the emergency department. It includes presentations for patients who do not wait for treatment once registered or triaged in the emergency department, those who are dead on arrival, and those who are subsequently admitted to hospital or to beds or units in the emergency department. An individual may have multiple presentations in a year. For further information, see the Non-admitted emergency department care NMDS 2015–16.

Episdode end status The episode end status indicates the status of the patient at the end of the non-admitted patient emergency department service episode. Further details on episode end status codes are available Non-admitted patient emergency department service episode end status .

Mental health‑related emergency department (ED)presentation

Mental health‑related emergency department (ED) presentation refers to an emergency department presentation that has a principal diagnosis that falls within the Mental and behavioural disorders chapter (Chapter 5) of ICD‑10‑AM (codes F00–F99) or the equivalent ICD‑9‑CM or SNOMED codes. It should be noted that this definition does not encompass all mental health‑related presentations to emergency departments, as detailed above. Additional information about this and applicable caveats can be found in the data source section.

Principal diagnosis

The principal diagnosis is the diagnosis established at the conclusion of the patient’s attendance in an emergency department to be mainly responsible for occasioning the attendance.


The triage category indicates the urgency of the patient’s need for medical and nursing care. It is usually assigned by an experienced registered nurse or medical practitioner at, or shortly after, the time of presentation to the emergency department. The triage category assigned is in response to the question: ‘This patient should wait for medical assessment and treatment no longer than...?’

The Australasian Triage Scale has 5 categories that incorporate the time by which the patient should receive care:

Resuscitation: immediate (within seconds)

Emergency: within 10 minutes

Urgent: within 30 minutes

Semi-urgent: within 60 minutes

Non-urgent: within 120 minutes.