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Printed on 7/21/2026
For informational purposes only. This is not medical advice.
The 4AT is a brief bedside delirium screening instrument assessing alertness, cognition (AMT4), attention, and acute/fluctuating change. It is designed for rapid use in routine care without special training, with score range 0-12.
Formula: 4AT total = alertness + AMT4 + attention + acute change/fluctuation (range 0-12).
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Begin by observing the patient's level of alertness during the interaction. Score alertness as 0 if the patient is normal (fully alert, not agitated), or 4 if clearly abnormal (agitated, drowsy, or fluctuating alertness). Then administer the 4-item Abbreviated Mental Test (AMT4): ask the patient their age, their date of birth, the location (hospital/clinic name), and the current year. Score AMT4 as 0 for no mistakes, 1 for one mistake or age/date uncertainty, or 2 for two or more mistakes or if the patient is untestable. The AMT4 provides a rapid cognitive anchor that detects acute cognitive change.
Ask the patient to recite the months of the year in reverse order, starting from December. Score as 0 if the patient can correctly name 7 or more months before making an error or stopping; 1 if the patient starts but names fewer than 7 months correctly or refuses midway; 2 if the patient is untestable (unable to attempt due to alertness, drowsiness, or severe agitation). Attention testing with months backward specifically detects inattention — the core cognitive feature of delirium — that may not be evident on brief orientation testing. Severely abnormal attention in an otherwise alert patient strongly suggests delirium or severe cognitive impairment.
Ask any available informant (nurse, caregiver, family member) or review nursing notes: Has there been any acute change in mental status or significant fluctuation in alertness, behavior, or cognition in the past 2 weeks? Score as 0 if no evidence of acute change or fluctuation, or 4 if evidence of acute onset or fluctuating course is present. Sum all four items: 4AT total = alertness + AMT4 + attention + acute change. Total range 0 to 12. Score of 4 or above = possible delirium (with or without underlying dementia). Score 1 to 3 = possible cognitive impairment. Score 0 = delirium unlikely (but clinical judgment still applies).
Hospitalist physicians, admitting nurses, rapid assessment nurses
The 4AT is designed for systematic delirium screening on hospital admission and at regular intervals throughout the inpatient stay. Its under-2-minute administration time and no special training requirement make it feasible for daily nursing delirium surveillance. Studies show that without structured screening tools, only 10 to 20 percent of delirium cases are detected by ward clinical staff. Implementing 4AT-based systematic screening significantly increases delirium detection rates, triggering timely investigation of underlying causes and implementation of non-pharmacological prevention and management strategies (ABCDEF bundle, HELP program).
Surgical nurses, post-anaesthesia care nurses, orthopedic ward staff, cardiac ICU nurses
Postoperative delirium occurs in 15 to 50 percent of older adults after major surgery and cardiac procedures. The 4AT is validated for postoperative delirium detection and is widely used in orthopedic surgery (hip fracture), cardiac surgery, vascular surgery, and other major procedure pathways. Multiple postoperative delirium prevention bundles now recommend 4AT assessment in the post-anaesthesia care unit and daily on the surgical ward. The 4AT's brevity enables integration into recovery room protocols without adding significant time burden to routine postoperative nursing assessments.
Emergency physicians, emergency nurses, rapid assessment teams
Delirium is present in 10 to 25 percent of older adults presenting to emergency departments and is frequently missed in the busy ED environment. The 4AT requires no specialized training, equipment, or extensive patient cooperation, making it feasible in the demanding ED context. A positive 4AT score in the ED triggers a structured delirium workup — urinalysis, CBC, BMP, medication review, sepsis screen — and informs admission decisions, as ED patients with delirium have substantially higher rates of in-hospital adverse events and 30-day mortality. Implementing routine 4AT screening in older ED patients aligns with ACEP and RCEM guideline recommendations for systematic cognitive assessment.
Care home nurses, nursing home physicians, geriatric liaison teams
Delirium in nursing home residents is particularly dangerous — it is frequently superimposed on baseline dementia, making detection more challenging, and is associated with very high mortality. The 4AT's design accounts for this by including a fluctuation item and allowing interpretation in the context of known baseline cognitive impairment. A 4AT score that is elevated relative to a known baseline — even if dementia is present — signals possible superimposed delirium requiring urgent assessment. The 4AT is included in multiple nursing home delirium management guidelines and is particularly useful for communicating suspected delirium to on-call physicians for remote assessment decisions.
ICU physicians, ICU nurses, critical care teams
While the CAM-ICU is typically used for ventilated ICU patients, the 4AT is well-suited for delirium monitoring in non-ventilated ICU patients who can verbally participate in testing. The 4AT's attention component (months backward) and AMT4 are feasible in cooperative ICU patients and provide rapid daily cognitive surveillance. Scores above 4 in ICU patients trigger review of sedation, analgesia, and potentially deliriogenic medications, early mobilization protocols, environmental orientation interventions, and CAM-ICU assessment if intubation is anticipated.
Clinical researchers, quality improvement teams, hospital administrators
The 4AT is one of the most widely validated delirium screening tools, with published accuracy data from systematic reviews showing sensitivity of 76 to 93 percent and specificity of 72 to 94 percent in diverse hospital populations. Its standardized format, free availability, and multilingual versions support use as a consistent delirium incidence tracking tool for hospital quality improvement programs. 4AT implementation studies have been used to document delirium detection rates, evaluate delirium prevention bundle effectiveness, and support audit and feedback cycles for improving delirium care quality across hospital systems.
The 4AT threshold of 4 is a screening threshold, not a diagnostic criterion. A positive 4AT indicates that delirium is possible and requires clinical assessment using formal diagnostic criteria (DSM-5 or ICD delirium criteria). Do not treat 4AT-positive patients pharmacologically for delirium before completing a clinical assessment — the positive screen should trigger investigation for underlying causes, not automatic sedation or antipsychotic administration.
The alertness item scores 0 or 4 — it has the highest weight in the 4AT. Clearly abnormal alertness (agitation, drowsiness, fluctuation during the assessment) contributes 4 points alone, which already reaches the delirium threshold. When you observe abnormal alertness at the start of the assessment, complete the full 4AT for documentation but recognize that this finding alone is highly predictive of delirium. Do not wait for all four items if the patient is clearly delirious — initiate the delirium workup while completing the assessment.
The acute change/fluctuation item cannot be accurately scored by the bedside clinician alone — it requires collateral information from a nurse, caregiver, family member, or review of recent nursing notes. Take 30 seconds to ask any available informant: 'Has [patient name] been more confused, less alert, or more agitated at any point in the last 2 weeks?' A positive informant report (score 4) dramatically increases 4AT sensitivity because delirium is defined by its fluctuating nature, which may not be apparent at any single time point of assessment.
The 4AT score of 0 makes delirium unlikely but does not exclude it. Delirium fluctuates — a patient who is delirious in the early morning may appear relatively normal at mid-morning when the 4AT is administered. If clinical concern for delirium persists despite a normal 4AT, repeat the assessment at a different time of day, particularly in the late afternoon and evening when delirium symptoms are typically most pronounced (sundowning).
A key advantage of the 4AT over tools like the CAM is that it was validated in populations with and without underlying cognitive impairment. The 4AT detects delirium superimposed on dementia — clinically one of the most challenging detection scenarios. When assessing a patient with known dementia, interpret the 4AT relative to their baseline cognitive function: a score elevated above their known baseline is clinically significant even if the absolute score is not dramatically high.
Months of the year in reverse order (December, November, October...) is more cognitively demanding than forward months and specifically taxes sustained attention — the cognitive function most impaired in delirium. A patient who can name months forward but fails the backward task has a selective attention deficit that is highly suspicious for delirium. In contrast, a patient who cannot name months in either direction likely has severe dementia or was never familiar with month names (education effect), which should be documented.
A positive 4AT score should not only trigger diagnostic evaluation — it should simultaneously trigger implementation of non-pharmacological delirium management strategies: reorientation (clock, calendar, frequent identification), sleep hygiene (minimize nighttime disruptions, avoid sedating medications at night), early mobilization (sitting up in bed, walking if able), sensory provision (glasses, hearing aids), and hydration support. The ABCDEF bundle and HELP (Hospital Elder Life Program) interventions are the most evidence-based non-pharmacological approaches.
Document 4AT results as the total score plus item-level breakdown: for example, '4AT score 6 (alertness 0, AMT4 2, attention 0, acute change 4).' This item-level documentation communicates which features of delirium are present, not just the total score. A patient with score 4 driven by acute change alone has a different clinical picture than one with score 4 driven by two AMT4 errors plus attention impairment. Item-level documentation also enables serial comparisons during treatment to track delirium resolution.
The 4AT has broad validation across hospital populations and uses a prespecified >=4 threshold for possible delirium.
Use in older adults and acutely unwell patients when rapid delirium triage is needed in emergency, ward, or perioperative settings.
Screening performance can be affected by severe sensory deficits, language barriers, and very severe baseline dementia.
Disclaimer: This tool is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about your health.
April 21, 2026 · trust-baseline
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Screen for delirium using the CAM (Confusion Assessment Method). Gold standard with ~94% sensitivity and ~89% specificity. Requires acute onset + inattention, plus disorganized thinking or altered consciousness.
OpenEmergencyScreen ICU patients for delirium using the CAM-ICU algorithm (acute/fluctuating change, inattention, consciousness, disorganized thinking).
OpenGeriatricsScreen for cognitive impairment using the 8-item AD8 informant interview (score 0-8).
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Open