4AT: 4 'A's Test
2011first public release4AT is a rapid four-part structured assessment combining observation of alertness, the Abbreviated Mental Test-4, an attention task and acute change or fluctuation. It is used to assess for current delirium in relevant non-ICU settings.
Chronology: First released online in 2011; first diagnostic-accuracy journal publication in 2014.
Classification
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Tool and original sources
View or download the complete 4AT below. It is licensed under CC BY 4.0 with attribution.
Original and selected diagnostic-accuracy papers
- Original paperBellelli G, Morandi A, Davis DH, Mazzola P, Turco R, Gentile S, et al. Validation of the 4AT, a new instrument for rapid delirium screening: a study in 234 hospitalised older people. Age and ageing. 2014;43(4):496-502. doi: 10.1093/ageing/afu021. PMID: 24590568.
This paper reports the original validation of 4AT. It reported sensitivity of 89.7% and specificity of 84.1% against an independent DSM-IV-TR clinical assessment.
Article PDF: CC BY. This licence applies to the article PDF and does not grant rights to reproduce the tool.
- Systematic review of diagnostic accuracyTieges Z, Maclullich AMJ, Anand A, Brookes C, Cassarino M, O'connor M, et al. Diagnostic accuracy of the 4AT for delirium detection in older adults: systematic review and meta-analysis. Age and ageing. 2021;50(3):733-743. doi: 10.1093/ageing/afaa224. PMID: 33951145.
This systematic review synthesised diagnostic-accuracy evidence for 4AT. Across 17 studies involving 3,702 observations, pooled sensitivity was 88% and specificity was 88%.
Article PDF: CC BY. This licence applies to the article PDF and does not grant rights to reproduce the tool.
- Selected diagnostic-accuracy studyShenkin SD, Fox C, Godfrey M, Siddiqi N, Goodacre S, Young J, et al. Delirium detection in older acute medical inpatients: a multicentre prospective comparative diagnostic test accuracy study of the 4AT and the confusion assessment method. BMC medicine. 2019;17(1):138. doi: 10.1186/s12916-019-1367-9. PMID: 31337404.
This diagnostic-accuracy study evaluated 4AT in emergency departments and acute medical wards at three UK centres against a DSM-IV clinical assessment. It reported sensitivity of 76% and specificity of 94% in 392 acute medical patients aged 70 years or older.
Article PDF: CC BY. This licence applies to the article PDF and does not grant rights to reproduce the tool.
At a glance
- Purpose
- Episodic assessment
- Population
- Adult
- Setting
- General / acute hospital, Emergency department, Perioperative
- Time
- ~2 min
- Items
- 4
- Score or threshold
- ≥4 = possible delirium; 1–3 = possible cognitive impairment
Format: Usually presented as a one-page bedside form. Patient and assessment details sit above four numbered sections covering alertness, brief cognitive testing, attention, and evidence of acute change or fluctuation. A boxed total score and short interpretation guide appear at the foot of the page.
- Strengths: No special training course or certification; supports assessment when cognitive testing is impossible because of drowsiness, agitation or severe illness; screens arousal and cognition
- Limitations: Not designed as a separate severity or motor-subtype scale
Guidance source: NICE CG103 recommendation 1.6.1 (2023) names 4AT outside critical care and post-anaesthetic recovery, and CAM-ICU or ICDSC in those settings.
Evidence
Reported sensitivity and specificity
Original/source study · 2014 — pmid:24590568
- Denominator
- Not stated: the source contains unresolved count inconsistencies
- Reference standard
- Separate expert geriatrician DSM-IV-TR assessment supported by short CAM, structured cognitive/arousal tests, interview, collateral information and clinical records
More evidence and citation details
- Full name
- 4 'A's Test
- Also known as
- 4 A's Test, 4 As Test, four AT
- Training
- No specific training course or certification required. Users should read the instrument instructions and understand delirium assessment.
- Evidence summary
- pooled
- Diagnostic-accuracy studies
- 34
- Reference standard
- Separate expert-geriatrician DSM-IV-TR assessment
- Related component tests
- AMT4 (Abbreviated Mental Test-4)
- Real-world use
- Completion was high in most included large studies; admission positive-score rates were 13–20% and postoperative rates 21–28%. These descriptive rates depend on case mix, timing and implementation and do not establish diagnostic accuracy. (Penfold 2024)
- Citation
- Bellelli G, Morandi A, Davis DH, Mazzola P, Turco R, Gentile S, Ryan T, Cash H, Guerini F, Torpilliesi T, Del Santo F, Trabucchi M, Annoni G, MacLullich AM Validation of the 4AT, a new instrument for rapid delirium screening: a study in 234 hospitalised older people Age and ageing. 2014;43(4):496-502. PMID 24590568
Copyright and reuse
- Version
- 1.2 (October 2014)
- Rights holder
- Alasdair MacLullich, Tracy Ryan and Jennifer Cash
- Licence
- CC-BY-4.0 ↗
- Information checked
- 2026-07-19
Instrument-specific terms apply. See the access and copyright policy or send a correction.
Sources checked 2026-07-24. How profiles are prepared.