🧠 4AT Rapid Delirium Screen
The 4AT is a rapid, training-free bedside screen for delirium and cognitive impairment, scoring alertness, AMT4, attention, and acute change.
Marked drowsiness/agitation or an acute fluctuating course each score 4, so either alone reaches the delirium threshold — reflecting their strong diagnostic weight. (original synthesis · not guideline verbatim)
Paste the link in Slack, Teams, X, or LinkedIn — the preview image comes from this page’s Open Graph card.
When to use
Score the four items at the bedside; sum them. A total ≥ 4 suggests possible delirium and triggers a search for precipitants, while 1–3 suggests cognitive impairment.
How it works
4AT = alertness (0 or 4) + AMT4 errors (0/1/2) + attention months-backward (0/1/2) + acute change/fluctuation (0 or 4). Bands: ≥4 possible delirium · 1–3 possible cognitive impairment · 0 unlikely.
Key points
- Marked drowsiness/agitation or an acute fluctuating course each score 4, so either alone reaches the delirium threshold — reflecting their strong diagnostic weight. (original synthesis · not guideline verbatim)
- It needs no special training and takes under 2 minutes, making it suitable for routine screening at admission and on change in status.
- A positive screen warrants a precipitant search (infection, hypoxia, drugs, metabolic, pain, retention) and is not itself a diagnosis.
References
- Bellelli G, et al. Validation of the 4AT, a new instrument for rapid delirium screening. Age Ageing. 2014;43(4):496-502.
- Shenkin SD, et al. Delirium detection in older acute medical inpatients: the 4AT diagnostic test accuracy study. BMC Med. 2019;17(1):138.
Worked calculation
The values below come from this tool's own example placeholders and are computed server-side with the formula shown on this page, so the arithmetic can be checked quickly. It demonstrates how to substitute values only — it is not clinical advice and not a real case.
| Alertness | Normal |
|---|---|
| AMT4 (age, date of birth, place, year) | No errors |
| Attention (months backward) | Correctly states ≥7 months |
| Acute change or fluctuating course | Absent |
→4AT0pts
- Interpretation：Delirium/cognitive impairment unlikely
| Alertness | Clearly abnormal (drowsy/agitated) |
|---|---|
| AMT4 (age, date of birth, place, year) | ≥2 errors / untestable |
| Attention (months backward) | Cannot start / untestable |
| Acute change or fluctuating course | Present |
→4AT12pts
- Interpretation：Possible delirium (± cognitive impairment)
Frequently asked questions
- What is 4AT Rapid Delirium Screen?
- The 4AT is a rapid, training-free bedside screen for delirium and cognitive impairment, scoring alertness, AMT4, attention, and acute change.
- How is 4AT Rapid Delirium Screen calculated? What is the core formula?
- 4AT = alertness (0 or 4) + AMT4 errors (0/1/2) + attention months-backward (0/1/2) + acute change/fluctuation (0 or 4). Bands: ≥4 possible delirium · 1–3 possible cognitive impairment · 0 unlikely.
- When is 4AT Rapid Delirium Screen used?
- Score the four items at the bedside; sum them. A total ≥ 4 suggests possible delirium and triggers a search for precipitants, while 1–3 suggests cognitive impairment.
- What are the key clinical points for 4AT Rapid Delirium Screen?
- Marked drowsiness/agitation or an acute fluctuating course each score 4, so either alone reaches the delirium threshold — reflecting their strong diagnostic weight. (original synthesis · not guideline verbatim) It needs no special training and takes under 2 minutes, making it suitable for routine screening at admission and on change in status. A positive screen warrants a precipitant search (infection, hypoxia, drugs, metabolic, pain, retention) and is not itself a diagnosis.
- What are the limits and cautions when using 4AT Rapid Delirium Screen?
- For licensed clinicians and clinical researchers. Interpret results with history, investigations and local protocols; not a diagnosis or prescription, and not a substitute for multidisciplinary decision-making or local guidelines.
- How is 4AT Rapid Delirium Screen calculated in practice? Can you show a worked example?
- Inputs: Alertness Normal, AMT4 (age, date of birth, place, year) No errors, Attention (months backward) Correctly states ≥7 months, Acute change or fluctuating course Absent → Result: 4AT 0 pts（Interpretation: Delirium/cognitive impairment unlikely） Inputs: Alertness Clearly abnormal (drowsy/agitated), AMT4 (age, date of birth, place, year) ≥2 errors / untestable, Attention (months backward) Cannot start / untestable, Acute change or fluctuating course Present → Result: 4AT 12 pts（Interpretation: Possible delirium (± cognitive impairment)）