4AT Calculator

The 4AT is a rapid screening instrument for delirium detection, designed for use at the bedside or in any clinical setting. It assesses four key features: Alertness, Abbreviated Mental Test-4 (AMT4), Attention (months backwards), and Acute change or fluctuating course.

Developed by Alasdair MacLullich and colleagues, the 4AT can be completed in under 2 minutes and requires no special training. It is designed to be practical for routine use by any healthcare professional.

The 4AT is scored from 0-12:

Item 1 (Alertness): 0 = normal, 4 = clearly abnormal Item 2 (AMT4): 0 = no mistakes, 1 = 1 mistake, 2 = 2+ mistakes or untestable Item 3 (Attention): 0 = achieves 7+ months correctly, 1 = less than 7, 2 = untestable Item 4 (Acute change): 0 = no, 4 = yes

Score 0: Delirium or severe cognitive impairment unlikely Score 1-3: Possible cognitive impairment — further assessment recommended Score 4+: Possible delirium ± cognitive impairment — urgent clinical assessment required

The 4AT is used in emergency departments, hospital wards, intensive care, aged care facilities, and post-surgical settings. It is suitable for initial screening — a positive result should trigger more comprehensive delirium assessment.

Unlike the Confusion Assessment Method (CAM), the 4AT does not require prior training and can be administered by any clinician. This makes it practical for routine use by nursing staff during admission assessments and ward rounds.

The 4AT is increasingly adopted in Australian hospitals as the preferred bedside delirium screening tool. It is endorsed by multiple Australian clinical guidelines and is used in the Australian Commission on Safety and Quality in Health Care's delirium clinical care standard.

The 4AT is licensed under Creative Commons BY and requires no permission, payment, or registration for use.