Normal, or mild sleepiness that settles within 10 s
Clearly abnormal — drowsy, or agitated/hyper-alert
2. AMT4 (age, date of birth, place, current year)
No mistakes
1 mistake
≥ 2 mistakes, or untestable
3. Attention (months of the year backwards)
Lists ≥ 7 months correctly
Starts but names < 7, or refuses
Untestable (unwell, drowsy, inattentive)
4. Acute change or fluctuating course
No
Yes — evidence of significant change or fluctuation in the last 2 weeks, still evident in the last 24 h
Answer all four items to calculate
Evidence
Original publication
Bellelli G, Morandi A, Davis DHJ, et al. Validation of the 4AT, a new instrument for rapid delirium screening: a study in 234 hospitalised older people. The 4AT (alertness, AMT4, attention via months backward, acute change) took under 2 minutes, needed no special training, and had 89.7% sensitivity and 84.1% specificity for delirium.
Age and Ageing, 2014
Open source
Guideline
SIGN 157 and NICE delirium guidance list the 4AT among recommended brief screening tools. Scoring: ≥ 4 suggests possible delirium ± cognitive impairment; 1–3 suggests possible cognitive impairment; 0 makes delirium (though not excluded) unlikely.
Last reviewed: 2026-09
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MedScore is an educational and clinical decision-support tool. It does not provide a diagnosis, a treatment, or a drug-dosing recommendation, and it does not replace clinical judgement or local guidelines. Confirm every result against the original source before acting on it. The treating clinician remains responsible for all decisions.