4AT (delirium / cognition)
Rapid delirium + cognitive screen (0–12).
What it is for
Acute confusion, home visits, frail older adults. ≥ 4 = possible delirium.
Use the working calculator
The working 4AT (delirium / cognition) calculator is on our calculators page. It is free and needs no account. Enter the values and it shows the result with the reading that goes with it.
The calculators are free. The trial opens the protocols and pathways they link to.What you enter
The calculator asks for 4 items.
- 1. AlertnessOptions: Normal / mild drowsy < 10 s; Clearly abnormal (drowsy or agitated)
- 2. AMT4 (age, DOB, place, current year)Options: No mistakes; 1 mistake; ≥ 2 mistakes / untestable
- 3. Attention — months of year backwardsOptions: ≥ 7 correct; Starts but < 7 / refuses; Untestable
- 4. Acute change or fluctuating courseOptions: No; Yes
How the result is read
The result is shown as 4AT, out of a maximum of 12.
The calculator reads each total as follows. Where a single answer changes the reading (for example sex, age or one extreme value), the working calculator says so.
| Total | Band | What the calculator says |
|---|---|---|
| 0 | Delirium / impairment unlikely | No evidence of delirium now. |
| 1 to 3 | Possible cognitive impairment | Further cognitive assessment when acute illness resolved. 1–3: cognitive impairment (delirium possible). |
| 4 to 12 | Possible delirium ± cognitive impairment | Assess for delirium — find & treat cause (infection, drugs, retention, pain, metabolic). TIME bundle. Delirium is a medical emergency in the frail. |
Sources
These are the sources the calculator cites. Check the current version before relying on a threshold.
Related
For qualified clinicians. A score supports a clinical decision and does not make it: check the inputs, read the cited source, and use the tools in your clinical system for patient care where one is provided.