4AT Score Calculator

4AT scoring table

The four items are scored and summed to give a total of 0 to 12. Items 1 and 4 carry 4 points each, which is why either alone can push a patient into the possible-delirium band.

Item 4 is answered from collateral history and the observations of staff, family or carers, over the previous two weeks and clearly evident in the last 24 hours.

4AT score interpretation

The 4AT is a screening tool. A positive screen prompts assessment for a cause, not a diagnosis on its own.

• 0Delirium or severe cognitive impairment unlikely

  Does not rule out delirium if acute change is present — repeat the assessment if the picture changes.

• 1–3Possible cognitive impairment

  Further testing recommended, for example 6CIT or ACE-III, and review for reversible causes.

• 4 or morePossible delirium, with or without cognitive impairment

  Investigate for an underlying cause, treat precipitants, review medication, and follow the local delirium pathway.

How to perform the 4AT

1. 1Observe the patient for level of alertness before you speak to them; if asleep, try to wake them with speech or gentle touch.
2. 2Ask the four AMT4 questions: age, date of birth, place (name of the hospital or building) and the current year.
3. 3Ask the patient to say the months of the year backwards, starting at December.
4. 4Establish from records, staff, family or carers whether there has been an acute change or fluctuation in mental function.
5. 5Add the four item scores and act on the total. Record the score and the time so that change can be tracked.

Common pitfalls

• Skipping item 4 because no collateral history is immediately available. Acute change is worth 4 points and is often the item that identifies hypoactive delirium.
• Missing hypoactive delirium — quiet, withdrawn patients are more often missed than agitated ones.
• Recording "untestable" as 0. An untestable attention or AMT4 item scores 2.
• Treating a positive 4AT as a diagnosis. It is a screen; the cause still has to be found.
• Using it once on admission only. Delirium fluctuates, so repeat screening is needed when the picture changes.

Frequently asked questions

When should the 4AT be used?

The 4AT is recommended as a first-line assessment for delirium in acutely unwell patients, particularly older adults in hospital. It should be performed on admission and whenever delirium is suspected. NICE and SIGN guidelines recommend it as a validated screening tool. It takes less than 2 minutes to complete.

How do you interpret the 4AT score?

A score of 0 means delirium or severe cognitive impairment is unlikely (but does not rule out delirium if acute change is present). A score of 1-3 indicates possible cognitive impairment - further testing recommended (e.g. 6CIT, ACE-III). A score of 4 or more indicates possible delirium with or without cognitive impairment - investigate for underlying cause.

What is the maximum 4AT score?

The maximum total is 12. Alertness and acute change each score 0 or 4, while AMT4 and attention each score 0, 1 or 2.

Does the 4AT require training to use?

No special training or certification is required, which is one reason it is widely adopted in UK acute care. It can be completed by any registered clinician as part of a routine assessment.

What is the difference between the 4AT and the CAM?

The Confusion Assessment Method is a structured diagnostic algorithm that generally requires training and a cognitive test to be performed first. The 4AT is a brief screening instrument designed for routine clinical practice, incorporating a short cognitive test within the tool itself.

Can the 4AT be used in patients who cannot speak?

Yes. Items that cannot be completed are scored as untestable rather than skipped, and the alertness and acute change items can still be assessed by observation and collateral history.

Sources and further reading

• The 4AT — rapid clinical test for delirium — 4AT (the4at.com)
• Delirium: prevention, diagnosis and management in hospital and long-term care (CG103) — NICE

This page is reference information for registered healthcare professionals. It is not medical advice and does not replace clinical judgement, local policy, or the current version of the source guidance. Always verify scores and thresholds against your own organisation's pathway before acting on them.