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Calculator · Rapid delirium and cognitive screen
4AT — Delirium Screen
A four-item bedside screen needing no special training and taking about two minutes. Designed for routine use in older or acutely unwell inpatients. A score of 4 or more suggests delirium — but the tool screens; it does not diagnose.
What it asks
| Criterion | Points |
|---|---|
| 1 · Alertness Includes patients who are markedly drowsy or agitated. Observe; if asleep, attempt to wake with speech or gentle touch. | Normal — fully alert but not agitated throughout — 0 Mild sleepiness < 10 seconds after waking, then normal — 0 Clearly abnormal — 4 |
| 2 · AMT4 Age, date of birth, place (name of hospital or building), current year. | No mistakes — 0 1 mistake — 1 2 or more mistakes, or untestable — 2 |
| 3 · Attention Ask the patient to list the months of the year backwards, starting at December. | Achieves 7 months or more correctly — 0 Starts but scores under 7 months, or refuses — 1 Untestable — too unwell, drowsy or inattentive — 2 |
| 4 · Acute change or fluctuating course Evidence of significant change or fluctuation in alertness, cognition or other mental function arising over the last 2 weeks and still evident in the last 24 hours. | No — 0 Yes — 4 |
How to read the score
| Score | Means | What to do |
|---|---|---|
| 0 | Delirium or cognitive impairment unlikely | Delirium and severe cognitive impairment both unlikely, though delirium is still possible if item 4 information is incomplete. |
| 1–3 | Possible cognitive impairment | Suggests cognitive impairment without delirium. Consider further cognitive assessment and review collateral history. |
| 4–12 | Possible delirium ± cognitive impairment | Screen positive. Look actively for a cause — infection, pain, constipation, urinary retention, drugs, hypoxia, electrolytes. Review the drug chart. Non-pharmacological management first. |
Before you use it
A positive 4AT is a prompt to search for a cause, not a diagnosis in itself. Delirium is a symptom — something is causing it.
Source: 4AT — Bellelli et al, Age and Ageing 2014 / SIGN 157
Checked, and shown
Every threshold on this page was checked against its primary source by a practising doctor. Here is what that involved, and what it found.