4AT Delirium Assessment
Rapid clinical test for delirium detection - designed for use at the bedside without special training.
1. Alertness
Observe the patient. If asleep, attempt to wake with speech or gentle touch.
2. AMT4 (Abbreviated Mental Test)
Ask: age, date of birth, place (hospital name), current year.
3. Attention
Ask patient to state the months of the year backwards, starting at December.
4. Acute change or fluctuating course
Evidence of significant change or fluctuation in alertness, cognition, or other mental function.
Select an option for each domain to calculate the 4AT score.
When to use the 4AT
The 4AT is recommended as a first-line assessment for delirium in acutely unwell patients, particularly older adults in hospital. It should be performed on admission and whenever delirium is suspected. NICE and SIGN guidelines recommend it as a validated screening tool. It takes less than 2 minutes to complete.
How to interpret
- Score 0: Delirium or severe cognitive impairment unlikely (but does not rule out delirium if acute change is present)
- Score 1-3: Possible cognitive impairment - further testing recommended (e.g. 6CIT, ACE-III)
- Score 4+: Possible delirium with or without cognitive impairment - investigate for underlying cause
Clinical context
The 4AT assesses four domains: alertness, abbreviated mental test (AMT4), attention (months backwards), and acute change or fluctuating course. A score of 4 or more should prompt investigation for precipitating causes of delirium including infection, medication effects, pain, constipation, urinary retention, and metabolic disturbance. The 4AT is validated in general hospital settings, emergency departments, and stroke units.
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