Objective This study aimed to investigate and collate the opinions of experts regarding the triage of patients in mental health crisis presenting to EDs.

Design A three-round e-Delphi study was conducted between November 2017 and April 2018. The panel of 28 representative experts were drawn from six stakeholder groups. 23 of the panel were clinicians working in England, while 5 were international triage experts.

Results Experts generated 173 statements in six topic areas in the first round. 32 of these statements reached consensus in round 2. A further 20 statements reached consensus in round 3, leaving 121 statements that did not reach consensus. The consensus statements were used to develop a structured five-level triage tool where the highest level of priority was assigned to patients exhibiting extreme aggression or agitation, those requiring restraint, those at immediate risk of leaving before assessment and those who presented a high risk of self-harm or harm to others. At lower triage priorities, other factors, such as items of psychiatric history, collateral history, observations and judgements, have been identified.

Conclusions A broadly based, multispecialty, multiprofessional expert Delphi panel has reached consensus on 52 statements concerning the triage of patients presenting in mental health crisis to EDs. The triage tool derived from this work can be used to inform the design of triage instruments employed to prioritise patients with physical and mental health problems equitably.