Emergency department or acute assessment unit: which is able to see and treat patients faster?

Key messages

Emergency departments see and treat people with urgent illnesses or injuries. Worldwide, emergency departments are experiencing challenges in delivering care to patients because of increasing numbers of people needing to use them.

• Acute assessment services are an alternative place for some patients to be seen and treated instead of the emergency departments and may help to ease long waiting times in the emergency departments.

• It is unclear how safe and effective acute assessment services are because there are no existing studies exploring these services.

What is an acute assessment service?

The acute assessment service is an alternative to the emergency department for some patients. They are thought to help in reducing long waiting times by grouping together people who have similar reasons for going to the emergency department and moving them to be seen by a doctor elsewhere. It is important to know if the acute assessment service does reduce waiting times for people who come to the emergency department, if it can help to reduce how long someone is admitted to the hospital, and if it is safe for people who are patients.

What did we want to find out?

We wanted to find out if the acute assessment service was able to see, treat, and discharge people faster than the emergency department. We also wanted to find out if the acute assessment service was associated with any unwanted effects for patients who were seen and treated by them.

What did we do?

We searched for studies that compared the emergency department with the acute assessment service for adults who went to the hospital for healthcare.

What did we find?

We were not able to find any studies that compared the emergency department with the acute assessment service.

How up-to-date is this evidence?

Studies published up to September 2022 were included in this review.

Authors' conclusions: 

At present there are no randomised controlled trials exploring the effects of acute assessment services on patient flow in hospital-based emergency departments compared to usual, ED-only care.

Read the full abstract...

Emergency departments (EDs) are facing serious and significant issues in the delivery of effective and efficient care to patients. Acute assessment services have been implemented at many hospitals internationally to assist in maintaining patient flow for identified groups of patients attending the ED. Identifying the risks and benefits, and optimal configurations of these services may be beneficial to those wishing to utilise an acute assessment service to improve patient flow.


To assess the effects of acute assessment services on patient flow following attendance at a hospital ED.

Search strategy: 

We searched MEDLINE, CENTRAL, Embase and two trials registers on 24 September 2022 to identify studies. No restrictions were imposed on publication year, publication type, or publication language.

Selection criteria: 

Studies eligible for inclusion were randomised trials and cluster-randomised trials with at least two intervention and two control sites. Participants were adults (as defined by study authors) receiving care either in the ED or the acute assessment service, where both were based in the hospital setting. The comparison was hospital-based acute assessment services with usual, ED-only care. The outcomes of this review were mortality at time point closest to 30 days, length of stay in the service (in minutes), and waiting time to see a doctor (in minutes).

Data collection and analysis: 

We followed the standard procedures of Cochrane Effective Practice and Organisation of Care for this review (https://epoc.cochrane.org/resources).

Main results: 

We identified a total of 5754 records in the search. Following assessment of 3609 de-duplicated records, none were found to be eligible for inclusion in this review.