4AT

• 1. Alertness
  Normal, or mildly sleepy <10 s after waking0Clearly abnormal4
• 2. AMT4 — age, date of birth, place, current year
  No mistakes01 mistake12 or more mistakes / untestable2
• 3. Attention — months of the year backwards
  Achieves 7 or more correctly0Starts but scores <7, or refuses1Untestable (unwell, drowsy, inattentive)2
• 4. Acute change or fluctuating course (last 2 weeks, still evident in last 24 h)
  NoYes

Source: NICE CG103 — Delirium: prevention, diagnosis and management

For healthcare professionals, as an aid to clinical judgement — not a substitute for it. Follow your local policy and ask a senior when in doubt.