The 4 'A's Test is a bedside medical scale used to help determine if a person has positive signs for delirium. The test is designed to be used as a detection tool in the general clinical settings, inpatient hospital setting outside of the Intensive Care Unit, or in the community. The 4AT is intended to be used by healthcare practitioners without the need for special training, and it takes around two minutes to complete. The test was first published online in 2011. The 4AT has been evaluated in multiple diagnostic test accuracy studies and it is used in both clinical practice and research. It has been included in clinical guidelines and policy documents.
Summary of the test
The 4AT has 4 parameters: Alertness, Abbreviated Mental Test-4 , Attention , and Acute Change or Fluctuating Course. The score range is 0–12, with scores of 4 or more suggesting possible delirium. Scores of 1-3 suggest possible cognitive impairment. There are several indications of a positive score of 4 or more. Parameters and can each individually trigger a positive score. The rationale is that both altered arousal and acute change in mental functioning are highly specific indicators of delirium. Parameters and provide embedded cognitive testing. These parameters can also yield an overall positive score for the 4AT: if scores as 2 or more mistakes or if the patient is untestable, and with the patient is untestable, then the combined score is 4, suggesting possible delirium. The rationale for allowing untestability to trigger an outcome of possible delirium is that many people with delirium are too drowsy or inattentive to undergo cognitive testing or interview. These scoring options additionally allow the 4AT to be completed in patients who are unable to provide verbal responses.
The 4AT is intended to be used to assess for delirium on initial presentation with the patient, in transitions of care, and when delirium is suspected.It is not intended to be routinely performed multiple times per day. The orientation and attention cognitive tests are not designed to be used repeatedly because of the burden on staff and patients, and because of practice effects. Shorter tests such as the National Early Warning Score - 2, RADAR, the Delirium Observation Scale, the, or the Nursing Delirium Screening Scale are more suitable for ongoing routine monitoring for new delirium after admission to hospital. A positive score in those tests generally then requires a more detailed assessment with a tool like the 4AT. This is an area of delirium practice which requires additional research. The 4AT is one of several other delirium assessment tools in the literature. Each varies in its intended use, completion time, need for training, and psychometric characteristics.
