The 4 'A's Test (4AT) is a straightforward and efficient tool used to screen for delirium and assess cognitive impairment. It involves evaluating four key components: alertness, cognitive orientation (AMT 4), attention, and recent changes in cognitive state. Each response is given a specific score that contributes to an overall total, which informs the interpretation of the patient's condition.

- **Alertness**: Evaluate the patient's alertness and categorize it as:
  - Normal: Score 0
  - Mild sleepiness for less than 10 seconds after waking, then normal: Score 0
  - Clearly abnormal: Score 4

- **AMT 4 (Cognitive Orientation)**: Ask the patient to state their age, date of birth, the name of the hospital or place, and the current year. Score based on the number of mistakes:
  - No mistakes: Score 0
  - 1 mistake: Score 1
  - Two or more mistakes, or if untestable: Score 2

- **Attention**: Ask the patient to list the months of the year in reverse order, starting from December:
  - Lists 7 or more months correctly: Score 0
  - Starts but lists fewer than 7 months, or refuses to start: Score 1
  - Untestable or cannot start because unwell: Score 2

- **Acute Change or Fluctuating Course**: Determine if the patient has experienced an acute change or fluctuation in mental state over the last two weeks, which persists in the last 24 hours:
  - No: Score 0
  - Yes: Score 4

Once all the responses are scored, sum these scores to get a total between 0 and 12. This total is then interpreted:

- A total score of 0 indicates that delirium or severe cognitive impairment is unlikely.
- Scores between 1 and 3 suggest possible cognitive impairment. 
- A score of 4 or higher indicates possible delirium and/or cognitive impairment.

The 4 A's Test, also known as the 4AT, is a clinical calculator used for delirium screening in patients. It is applicable to a wide range of patient populations, particularly those in acute hospital settings, intensive care units, and long-term care facilities. The 4AT is designed to quickly and accurately identify patients who may be suffering from delirium, a common and serious cognitive disorder. The test assesses four areas: alertness, AMT4 (a brief memory test), attention, and acute change or fluctuating course. The 4AT is particularly useful because it does not require any special training to administer and can be completed in under 2 minutes. There are no specific exclusion criteria for its use, making it a versatile tool for healthcare professionals.

4 'A's Test (4AT) for delirium screening