For healthcare professionals
4AT Delirium Test
The 4AT is a short bedside test to screen for delirium. It has four items: alertness, the Abbreviated Mental Test 4 (AMT4), attention with the months of the year backwards, and acute change or fluctuating course. The total runs from 0 to 12, and 4 or above suggests possible delirium. Bellelli and colleagues published its validation in 2014. This calculator is written for clinicians and is not a diagnosis.
Items
Choose the finding for each item. Nothing you enter leaves this page.
What you will see
The total from 0 to 12 and what the score range suggests.
Educational only, not medical advice. Not a diagnosis. Treatment decisions belong to the treating team.
Source
Bellelli G and colleagues, Age and Ageing 2014 (open access, CC BY): items, total range and the meaning of 0, 1 to 3 and 4 or above. Item points as printed in Table 1 of Soboh R and colleagues, BMC Geriatrics 2024 (CC BY). The tests check every item, the band edges and the examples given by Bellelli.
Validated in
Bellelli 2014 studied 234 patients aged 70 or older admitted to an acute geriatric ward or a rehabilitation unit; people with no verbal communication, coma (RASS -4 or lower), learning disability or severe hearing disability were excluded. Later studies include older adults with hip fracture (Spyraki 2026) and 75,221 older adult hospital admissions (Penfold 2025).
Limits
The 4AT is a screening test, not a diagnosis. The 3/4 cut-off was not derived in the validation study, and severe long-standing cognitive impairment can also give a score of 4 (Bellelli 2014). A score of 0 holds only if the information on acute change or fluctuation is complete (Spyraki 2026). An Age and Ageing corrigendum to Bellelli 2014 exists (PMID 25477307); we could not read its text.
4AT scoring
Add the points for each item (Soboh 2024). The total runs from 0 to 12 (Bellelli 2014).
Alertness (drowsiness or sleepiness)
- Normal, or mild brief sleepiness: 0
- Clearly abnormal: 4
AMT4 (age, date of birth, place, current year)
- No mistakes: 0
- 1 mistake: 1
- 2 or more mistakes, or untestable: 2
Attention (months of the year backwards, starting with December)
- 7 or more months correct: 0
- Fewer than 7 months: 1
- Untestable: 2
Acute change or fluctuating course in mental function
- No: 0
- Yes: 4
Being untestable on the AMT4 and on the months backwards each scores 2, so being untestable on both gives 4 (Bellelli 2014).
What the score suggests
| Score | Suggests |
|---|---|
| 0 | Delirium and moderate to severe cognitive impairment unlikely |
| 1 to 3 | Possible moderate to severe cognitive impairment |
| 4 or above | Possible delirium |
Score ranges as given by Bellelli and colleagues (Bellelli 2014); the same three groups are used by Penfold and colleagues (Penfold 2025).
Worked example from the validation paper: a drowsy, untestable patient with a clear change in mental status scores 4 + 2 + 2 + 4 = 12 (Bellelli 2014).
What the studies found
In the 2014 validation study, the 4AT had a sensitivity of 89.7% and a specificity of 84.1% for delirium. The alertness and acute change items were highly specific, while the AMT4 and months backwards items were sensitive. No specific training in the 4AT was given (Bellelli 2014).
In older adults with hip fracture, a Greek version with a cut-off of 4 or above had a sensitivity of 87.5% and a specificity of 91.1% (Spyraki 2026).
Related calculators
To rate agitation and sedation, see the Richmond Agitation-Sedation Scale. For level of consciousness, see the Glasgow Coma Scale. Other bedside scores are listed under For healthcare professionals.
In the intensive care unit, the CAM-ICU delirium algorithm is used to screen for delirium.
Sources
- Bellelli G, Morandi A, Davis DH, 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. doi:10.1093/ageing/afu021. PMID 24590568. Open access (CC BY 3.0). Methods (items, scoring 0 to 12, meaning of 0, 1 to 3 and 4 or above), Results and Discussion. Corrigendum: Age Ageing 2015, PMID 25477307. pmc.ncbi.nlm.nih.gov/articles/PMC4066613/
- Soboh R, Gino-Moor S, Jiris N, Ginsberg S, Oliven R. Validation of a viable delirium detection test performed by nurses and physicians during routine patient care. BMC Geriatr. 2024;24(1):297. doi:10.1186/s12877-024-04884-8. PMID 38549098. Open access (CC BY). Table 1 (4AT parameters and scoring). pmc.ncbi.nlm.nih.gov/articles/PMC10976736/
- Spyraki M, Dimitriou E, Antzoulas P, et al. Translation, cultural adaptation, and validation of the Greek version of the 4 'A's Test for delirium screening in elderly patients with hip fracture. Clin Pract. 2026;16(3):58. doi:10.3390/clinpract16030058. PMID 41892502. Open access (CC BY). Methods (score of 0 and complete information on acute change) and Results. pmc.ncbi.nlm.nih.gov/articles/PMC13025903/
- Penfold RS, Bowman E, Vardy ERLC, et al. Using scores from the 4AT delirium detection tool as an indicator of possible dementia: a study of 75 221 older adult hospital admissions. Age Ageing. 2025;54(6):afaf144. doi:10.1093/ageing/afaf144. PMID 40518970. Open access (CC BY). Methods (4AT score groups 0, 1 to 3 and 4 or above). pmc.ncbi.nlm.nih.gov/articles/PMC12167849/
Written and maintained by the uncovermyrisk.com editorial team. We do not have a medical reviewer; every claim links to its primary source above. Last reviewed: 2026-11-02. Spotted an error? See About.