🧠 4AT Rapid Delirium Screen
The 4AT is a rapid, training-free bedside screen for delirium and cognitive impairment, scoring alertness, AMT4, attention, and acute change.
4AT Rapid Delirium Screen
Alertness
AMT4 (age, date of birth, place, year)
Attention (months backward)
Acute change or fluctuating course
When to use
Score the four items at the bedside; sum them. A total ≥ 4 suggests possible delirium and triggers a search for precipitants, while 1–3 suggests cognitive impairment.
How it works
4AT = alertness (0 or 4) + AMT4 errors (0/1/2) + attention months-backward (0/1/2) + acute change/fluctuation (0 or 4). Bands: ≥4 possible delirium · 1–3 possible cognitive impairment · 0 unlikely.
Key points
- Marked drowsiness/agitation or an acute fluctuating course each score 4, so either alone reaches the delirium threshold — reflecting their strong diagnostic weight. (original synthesis · not guideline verbatim)
- It needs no special training and takes under 2 minutes, making it suitable for routine screening at admission and on change in status.
- A positive screen warrants a precipitant search (infection, hypoxia, drugs, metabolic, pain, retention) and is not itself a diagnosis.
References
- Bellelli G, et al. Validation of the 4AT, a new instrument for rapid delirium screening. Age Ageing. 2014;43(4):496-502.
- Shenkin SD, et al. Delirium detection in older acute medical inpatients: the 4AT diagnostic test accuracy study. BMC Med. 2019;17(1):138.
Decision support for licensed clinicians only; not a substitute for clinical judgement, diagnosis or local protocols.