What goes into the 4AT (delirium)
- Alertness: Normal, or mildly sleepy < 10 s after waking (0); Clearly abnormal (4)
- AMT4 (age, date of birth, place, year): No mistakes (0); 1 mistake (1); 2 or more mistakes, or untestable (2)
- Attention (months of the year backwards): 7 or more months correct (0); Starts but < 7 months, or refuses (1); Untestable (too unwell, drowsy, inattentive) (2)
- Acute change or fluctuating course: No (0); Yes (4)
How to interpret the result
- 0: delirium or severe cognitive impairment unlikely
- 1–3: possible cognitive impairment
- ≥ 4: possible delirium ± cognitive impairment
Clinical pearls
- A positive screen is not a diagnosis; confirm clinically and look for causes (infection, drugs, retention, constipation, pain, withdrawal).
- Hypoactive delirium is common and easily missed.
- Non-drug measures come first; in AID-ICU (2022) haloperidol did not significantly improve days alive and out of hospital in ICU delirium.
Evidence
- Bellelli G, et al. Validation of the 4AT, a new instrument for rapid delirium screening: a study in 234 hospitalised older people. Age Ageing. 2014;43:496-502.
Related workups
Related calculators
For education only. Check the inputs and the population the score was validated in before acting on it. Not a substitute for clinical judgment.