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CAC-A: Clinical Assessment of Confusion-A

1990

A 25-item nurse-observed measure of acute confusion across five behavioural dimensions. It has later delirium criterion-validity evidence, but its construct is broader than criterion-based delirium diagnosis.

At a glance

Purpose
Episodic assessment
Population
Adult
Setting
General / acute hospital
Time
approximately 5 min after observation
Items
25
Score or threshold
Higher totals indicate greater confusion; later studies have used five or more abnormal behaviours for case-finding

Format: CAC-A aggregates 25 observed behaviours across five dimensions to describe acute confusion. The complete form is not supplied by an information card. Consult the original instrument publication for the operational method.

Primary validation papers

2 identified diagnostic-accuracy papers

Other forms of validation are described in the evidence section. What is counted?

Large-scale clinical implementation

Not yet reviewed.

A focused implementation review has not yet been completed for this profile.

Training and instructions

Public training resources have not yet been confirmed in this review. Check the linked developer or original source for instructions.

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Tool and original sources

This record describes a method rather than a downloadable bedside form. The main source is linked below.

NIDUS information cards ↗

Original and selected diagnostic-accuracy papers

  • Original paperVermeersch PE. The clinical assessment of confusion-A. Applied nursing research : ANR. 1990;3(3):128-33. doi: 10.1016/s0897-1897(05)80132-6. PMID: 2400212.

    This is the original published source for CAC-A itself. It is the main source for the method, its intended use and the evidence available at publication.

    Open PubMed ↗
  • Selected diagnostic-accuracy studyPompei P, Foreman M, Cassel CK, Alessi C, Cox D. Detecting delirium among hospitalized older patients. Archives of internal medicine. 1995;155(3):301-7. doi: 10.1001/archinte.1995.00430030095011. PMID: 7832602.

    This diagnostic-accuracy study evaluated CAC-A in four medical and surgical wards of a university teaching hospital against a DSM-III-R clinical assessment. It reported sensitivity of 36% and specificity of 95% in 432 hospitalised adults aged 65 years or older; 64 developed delirium.

    Open PubMed ↗
Multiple DTA studies identifiedCore instrument family
Classification

Classification

Episodic assessmentMonitoring for new onset deliriumDetailed phenomenological and/or neuropsychological assessment

A tool may belong to more than one category. Select a linked category to see other relevant profiles.

Evidence

Diagnostic-accuracy evidenceMultiple DTA studies identified

Reported sensitivity and specificity

Headline metric source

Later validation or evaluation · 1995; pmid:7832602

Denominator
Reported source unit: 432 (analysis unit not fully reconciled)
Reference standard
One of five clinician investigators (four geriatricians, one geriatric nurse specialist) applying operationalised DSM-III-R delirium criteria within 24 hours of referral
36%
Sensitivity
95%
Specificity

Earliest DTA evaluation identified in the current audit; see the linked source and methodological caveats.

More evidence and citation details
Full name
Clinical Assessment of Confusion-A
Also known as
CAC-A, Clinical Assessment of Confusion A
Related profiles
CAC-B
Evidence summary
single-DTA
Diagnostic-accuracy evaluations
2
Reference standard
One of five clinician investigators (four geriatricians, one geriatric nurse specialist) applying operationalised DSM-III-R delirium criteria within 24 hours of referral
Citation
Vermeersch PE The clinical assessment of confusion-A Applied nursing research : ANR. 1990;3(3):128-33. PMID 2400212
Download RIS ↗ Download BibTeX ↗

Primary validation studies

Distinct primary publications from the current diagnostic-accuracy audit. Reviews and repeated evaluations within one paper are not counted again. Overlapping cohorts have not all been reconciled. Read the counting rules and limitations.

Open 2 identified papers
  1. Pompei P, Foreman M, Cassel CK, Alessi C, Cox D (1995). Detecting delirium among hospitalized older patients. Archives of internal medicine.

    Reference category: other comparator or secondary accuracy evidence.

  2. Cacchione PZ (2002). Four acute confusion assessment instruments: reliability and validity for use in long-term care facilities. Journal of gerontological nursing.

    Reference category: other comparator or secondary accuracy evidence.

Copyright and reuse
Information checked
2026-07-19

Instrument-specific terms apply. See the access and copyright policy or send a correction.

Base clinical review: 2026-07-29. Instrument description source check: 2026-09-05. Scope and limitations.