How to choose a delirium assessment tool
There is no single “best” tool; the right choice depends on the clinical question, setting, patient population, administration and available training. Start with these questions, then use the directory filters to examine relevant tools.
No single instrument is endorsed. Check the evidence, instructions, training requirements and permissions for any tool you are considering. Local guidelines and available training should guide the final choice; see Methodology and Disclosures.
1. What are you trying to do?
Find structured tools for first presentation or another time when delirium is suspected.
See episodic assessment tools Observe seriallyFind instruments intended for repeated observation across a shift or episode of care.
See serial-observation tools Measure severity or courseFind instruments that grade severity or track change over time.
See severity tools Estimate future riskFind named models that estimate who may develop delirium later, kept separate from current assessment.
See prediction models2. Where are you, and who is the patient?
Setting and population change which tools are suitable and practical. Start with a common route, then inspect each profile and its source population.
3. Check the instructions and routine-care evidence
Start with the current manual. Then look at studies from settings like yours. Check who performed the assessment, who was included, whether assessments were completed and what followed a concerning result.
For people with indicators of delirium, NICE CG103 (2023) recommends the 4AT outside critical care and post-anaesthetic recovery. It recommends CAM-ICU or ICDSC in those settings. A tool result informs clinical assessment; it is not the whole assessment.
Follow the perioperative pathway · Read about monitoring during a stay.
Getting detection right
- Select carefully and use consistently. Choose an assessment validated for the relevant population and setting, then follow its current instructions.
- Assess risk and observe systematically. When indicators of delirium are present, use an appropriate validated assessment in line with local guidance; a negative result does not override clinical concern. Hypoactive delirium is easily missed.
- Notice abnormal arousal. Altered arousal can support assessment, but it is not synonymous with delirium and requires clinical interpretation.
- Interpret every result clinically. A result indicating possible delirium prompts assessment for delirium and its causes; a negative result should not overrule continuing concern.
- 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.