4AT — 4 'A's Test
2011Rapid bedside screen incorporating alertness, the Abbreviated Mental Test-4, attention and acute change/fluctuation. NICE recommends the 4AT when delirium indicators are identified outside critical care and post-anaesthetic recovery; use CAM-ICU or ICDSC in those settings. No special training course or certification is required, but users should read the instructions and be competent to apply it.
89.7%
Sensitivity*
84.1%
Specificity*
n=234
Sample
Full name4 'A's Test
Also known as4 A's Test, 4 As Test, four AT, AMT4
PurposeUltra-brief bedside screen
PopulationAdult
SettingGeneral / acute hospital, Emergency department, Perioperative
Items4
Administration~2 min
EvidencePooled diagnostic-accuracy evidence
Reference typeOriginal validation study
Reference standardDSM-IV-TR (geriatrician)
Validation samplen = 234
Cut-off / scoring≥4 = possible delirium; 1–3 = possible cognitive impairment
Strengths＋ No special training course or certification; usable in drowsy/uncooperative patients; screens arousal and cognition
Limitations− A screen, not a diagnostic algorithm; does not grade severity
Real-world useCompletion 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)
ReferenceBellelli 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. Age Ageing. 2014;43(4):496-502. PMID 24590568
Key studies
* Where shown, sensitivity/specificity are from the cited validation cohort and are not pooled estimates. Citation metadata was checked against PubMed or the publisher DOI record; a checked reference does not imply validation, study quality or endorsement. See the Methodology.