Choosing a delirium assessment tool
There is no single “best” tool — the right choice depends on your goal and your setting. Start with these two questions, then use the setting-by-setting suggestions below.
The suggestions here are examples grounded in validation evidence for each setting, not endorsements, and usually list more than one option. This directory is curated by a co-author of the 4AT; see Methodology and Disclosures. Local guidelines and available training should guide the final choice.
1. What are you trying to do?
- Screen / case-find Use a brief structured assessment when risk review, observation or clinical concern identifies possible delirium.
- Diagnose Confirm delirium in a structured way once suspicion is raised.
- Measure severity Grade and track how severe the delirium is over time.
- Monitor Repeatedly re-assess to catch onset or resolution.
2. Where are you, and who is the patient?
Setting and population change which tools are validated and practical. A ventilated ICU patient, a child, a person at the end of life, and a walking patient in the ED all need different approaches. The suggestions below are grouped accordingly.
Filter the full directory yourselfSuggestions by setting
General ward & acute medicine
Screen: 4AT (no special course or certification; read the instructions; ~2 min) · UB-2 as a first step.
Diagnose: 3D-CAM or CAM (trained raters).
Monitor: Nu-DESC or DOS across shifts.
Emergency department
Two-step: Delirium Triage Screen (rule-out) → bCAM (rule-in).
Alternatives: 4AT at the front door · mCAM-ED pathway.
Intensive care (adult)
Screen/assess: CAM-ICU or ICDSC (validated for ventilated patients).
Severity: CAM-ICU-7.
Perioperative & surgery
Screen: 4AT pre- and post-operatively.
Diagnose: 3D-CAM.
Monitor: DOS. Arousal-based tools (OSLA, mRASS) help in recovery.
Palliative & end-of-life care
Screen: Single Question in Delirium (SQiD) · Nu-DESC.
Severity: MDAS (developed in this population).
Care home & community
Screen: 4AT · RADAR (≈7 seconds on medication rounds).
Informant-based: SQiD, FAM-CAM, Sour Seven for family/carer input.
Children & young people
PICU: CAPD (all ages) · pCAM-ICU (≥5 y) · psCAM-ICU (infants/preschool).
Post-anaesthesia: PAED measures emergence delirium/agitation; it is not a general PICU delirium instrument and pain or anxiety can affect scores.
Research & severity measurement
Severity: DRS-R-98, MDAS, CAM-S.
Motor subtype: DMSS.
Objective attention: DelApp.
Getting detection right
- Use a validated tool, consistently. A good tool used routinely beats a “perfect” tool used occasionally.
- Assess risk and observe systematically. When indicators of delirium are present, use an appropriate validated assessment in line with local guidance; a negative screen does not override clinical concern. Hypoactive delirium is easily missed.
- Assess arousal first. An abnormal level of arousal is a fast, powerful pointer to delirium.
- A positive screen triggers a full assessment for delirium and its causes — it is a prompt, not a diagnosis.
- Match the tool to the rater. Use instruments for which staff have read the instructions and are competent; some require a formal training process and others do not.