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4AT (delirium screen)

Rapid delirium and cognitive-impairment screen for adults in acute care

Sources last checked: 2026-10-13

4AT (delirium screen)

Rapid delirium and cognitive-impairment screen for adults in acute care

1. Alertness
2. AMT4: age, date of birth, place, current year
3. Attention: months of the year backwards
4. Acute change or fluctuating course
Fill in every field to see the result.

4AT © 2011–2014 Alasdair MacLullich, Tracy Ryan and Helen Cash, CC BY 4.0; item wording here is abbreviated and the German and Turkish labels are Medelix translations, not official 4AT translations — official version at the4at.com. A screening tool, not a diagnosis. For ICU patients, CAM-ICU or ICDSC are recommended instead.

Source: 4AT version 1.2 © 2011–2014 Alasdair MacLullich, Tracy Ryan and Helen Cash, licensed under CC BY 4.0. Validation: 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(4):496-502.Open

Interpretation

0 — delirium or severe cognitive impairment unlikelyDelirium remains possible if the information for item 4 is incomplete.
1–3 — possible cognitive impairmentDelirium is less likely; the result points to possible cognitive impairment.
≥ 4 — possible delirium ± cognitive impairmentNot a diagnosis: a positive screen for possible delirium; the diagnosis and its causes are established by clinical assessment.

What is the 4AT (delirium screen)?

The 4AT is a four-item screening test for delirium and cognitive impairment that takes under two minutes and needs no special training. It was developed by Alasdair MacLullich and colleagues in Edinburgh (version 1.2, 2014) and validated in hospitalised older people (Bellelli, Age Ageing 2014). It is free to use under a CC BY 4.0 licence and recommended by SIGN 157 and the German AWMF S3 delirium guideline 2025.

When to use it

  • Older adults on arrival in the emergency department or on admission to medical or surgical wards.
  • Patients with suspected acute confusion, including those who are drowsy or agitated.
  • Repeated screening after surgery or when the clinical state changes.

When not to use it

  • Intensive care patients — CAM-ICU or ICDSC are recommended there.
  • Children and adolescents — not validated.
  • As a substitute for a full diagnostic assessment against DSM/ICD criteria.

How it is calculated

CriterionPoints
1. Alertness
Normal (fully alert, not agitated) or mild sleepiness < 10 s after waking0
Clearly abnormal (markedly drowsy, or agitated/hyperactive)4
2. AMT4: age, date of birth, place, current year
No mistakes0
1 mistake1
2 or more mistakes, or untestable2
3. Attention: months of the year backwards
7 or more months correct0
Starts but < 7 months correct, or refuses to start1
Untestable (cannot start: unwell, drowsy, inattentive)2
4. Acute change or fluctuating course
No0
Yes4

Clinical pearls and limitations

  • 4AT © 2011–2014 Alasdair MacLullich, Tracy Ryan and Helen Cash, CC BY 4.0; item wording here is abbreviated and the German and Turkish labels are Medelix translations, not official 4AT translations — official version at the4at.com. A screening tool, not a diagnosis. For ICU patients, CAM-ICU or ICDSC are recommended instead.
  • Patients who cannot be tested score as 'untestable' on items 2 and 3, so very drowsy patients still screen positive.
  • Item 4 needs collateral history — from relatives, carers, notes or staff.
  • Pooled sensitivity and specificity were both about 88 % in a 2021 meta-analysis.
  • A score of 1–3 suggests cognitive impairment rather than delirium, but does not exclude delirium.

Frequently asked questions

Is the 4AT free to use?

Yes. It is released under CC BY 4.0; no permission, payment or registration is needed, provided the authors and licence are credited.

What 4AT score suggests delirium?

A score of 4 or more indicates possible delirium with or without cognitive impairment; it is a screening result, not a diagnosis.

What are the four 'A's?

Alertness, AMT4 (orientation questions), Attention (months backwards) and Acute change or fluctuating course.

Can the 4AT be used in people with dementia?

Yes, it was validated in older inpatients including people with dementia, but a positive result does not by itself distinguish delirium from dementia, because the two overlap.

Evidence and guidelines

  1. Primary source: 4AT version 1.2 © 2011–2014 Alasdair MacLullich, Tracy Ryan and Helen Cash, licensed under CC BY 4.0. Validation: 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(4):496-502.
  2. Bellelli G et al. Age Ageing 2014;43(4):496-502.
  3. Tieges Z et al. Diagnostic accuracy of the 4AT for delirium detection in older adults: systematic review and meta-analysis. Age Ageing 2021;50(3):733-743.
  4. SIGN 157. Risk reduction and management of delirium, 2019 — '4AT should be used … in emergency department and acute hospital settings'.
  5. S3-Leitlinie Delir im höheren Lebensalter (AWMF-Register 109-001), 2025 — Empfehlungen 2.7–2.9.
  6. Creative Commons Attribution 4.0 International licence.

Have a follow-up question?

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