CAM — Confusion Assessment Method
1990The most widely used and studied delirium diagnostic algorithm worldwide; operationalises DSM criteria into four features (acute onset/fluctuation, inattention, disorganised thinking, altered consciousness).
94–100%
Sensitivity*
90–95%
Specificity*
n=56
Sample
Full nameConfusion Assessment Method
PurposeDiagnostic assessment (episodic)
PopulationAdult
SettingGeneral / acute hospital
Items4
Administration5 min
EvidencePooled diagnostic-accuracy evidence
Reference typeOriginal validation study
Reference standardDSM-III-R (psychiatrist)
Validation samplen = 56
Cut-off / scoringFeatures 1 AND 2, and (3 OR 4)
ReliabilityInter-rater κ 0.81–1.0
Strengths＋ Reference algorithm; very high specificity; basis of many derivative tools
Limitations− Performance depends on training and on scoring during formal cognitive testing
Real-world useCompletion varied widely (up to 99% in dedicated programmes, lower elsewhere); admission positive-score rates were 8–51% and inpatient rates 2–20%. Low rates may reflect case mix, timing, selective completion or under-detection and should prompt local audit rather than a single conclusion. (Penfold 2024)
ReferenceInouye SK, van Dyck CH, Alessi CA, et al. Clarifying confusion: the confusion assessment method. A new method for detection of delirium. Ann Intern Med. 1990;113(12):941-8. PMID 2240918
Key studies
* Where shown, sensitivity/specificity are from the cited validation cohort and are not pooled estimates. Citation metadata was checked against PubMed or the publisher DOI record; a checked reference does not imply validation, study quality or endorsement. See the Methodology.