What is the CAM-S and how does it differ from the CAM?

The Confusion Assessment Method Severity Score (CAM-S) extends the standard CAM from a binary diagnostic tool to a continuous severity measure. While CAM determines whether delirium is present or absent, CAM-S quantifies how severe the delirium features are on a numerical scale.

What are the CAM-S score ranges?

The short form scores 0–7 based on four core CAM features. The long form scores 0–19 based on ten features. Higher scores indicate greater delirium severity in both versions.

CAM-S was developed by Sharon K. Inouye and colleagues. The validation study was published in Annals of Internal Medicine in 2014.

What clinical outcomes does CAM-S predict?

Higher cumulative CAM-S scores during hospitalisation are associated with longer length of stay, greater functional decline at discharge, increased nursing home placement, and higher 90-day mortality.

Is CAM-S valid for use in older adults with dementia?

CAM-S can be used in patients with dementia as a delirium-superimposed-on-dementia severity measure, but baseline cognitive status should be documented separately to contextualise scores.

How does CAM-S compare to the DRS-R98?

The DRS-R98 is a 16-item clinician-rated scale used widely in psychiatric research. CAM-S has the advantage of direct integration with the CAM diagnostic framework and nursing-friendly administration.

Can nurses administer CAM-S reliably?

Yes. CAM-S has been validated for nursing administration with appropriate training. The short form is particularly suited to nursing-led delirium monitoring programmes.

What does the altered level of consciousness item capture?

Altered consciousness in CAM-S reflects deviation from alert wakefulness — including hypervigilant/agitated and lethargic/stuporous states. It carries significant prognostic weight in outcome studies.

How should CAM-S data be used in clinical notes?

Document CAM-S score alongside CAM result, time of assessment, and brief description of observable behaviours. This creates a longitudinal severity record supporting communication across shifts and providers.

Is there a specific cutoff score that indicates severe delirium?

Formal severity categories have not been universally standardised. Clinically, any CAM-S short form score of 5–7 or long form score of 14–19 reflects severe delirium burden warranting urgent review.

Can CAM-S be used to guide medication dosing in delirium?

CAM-S can inform the intensity of management but should not be used as a sole dosing guide. Medication decisions should be based on full clinical assessment, with CAM-S as one contextual input.

Online Medical Tools — CAM-S

Printed on 9/3/2026

For informational purposes only. This is not medical advice.

Geriatrics

CAM-S

CAM-S extends Confusion Assessment Method logic to quantify delirium severity. It is used clinically and in research to monitor delirium symptom burden trends and treatment response.

Formula: CAM-S total is a summed delirium-severity score (commonly represented on 0-19 range).

CAM-S total score

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How It Works

Confirm CAM Delirium Diagnosis First

CAM-S is a severity scoring extension of the standard CAM. It should only be applied in patients who have been assessed using the CAM algorithm. The severity score quantifies how severe the features are, not whether delirium is present.

Rate Each CAM Feature for Severity

The long form rates 10 CAM features on a multi-point scale for a total of 0–19. The short form rates 4 features (acute onset/fluctuation, inattention, disorganised thinking, altered level of consciousness) on a 0–7 scale. Each feature is scored based on severity rather than a simple yes/no.

Track Trajectory Over Time

Record CAM-S at each delirium assessment interval. Increasing scores indicate worsening delirium burden; decreasing scores indicate improvement. The trajectory of CAM-S over days is more clinically meaningful than any single measurement.

Who Uses the CAM-S

Delirium Severity Tracking in Inpatient Care

Geriatricians, hospitalists, and inpatient nurses

Serial CAM-S scoring documents whether a patient's delirium is worsening, stable, or improving, informing decisions about treatment escalation or step-down.

Clinical Trial Delirium Endpoint Measurement

Clinical researchers and trial coordinators

CAM-S provides a continuous severity outcome measure for delirium intervention trials, offering greater statistical power than the binary CAM diagnosis (present/absent) as a primary or secondary endpoint.

Post-operative Delirium Monitoring

Surgical teams and post-anaesthetic care nurses

After surgery, CAM-S tracks the trajectory of post-operative delirium — typically peaking at 24–48 hours and resolving over days — helping teams gauge whether natural resolution is occurring or intervention is needed.

Treatment Response Assessment

Psychiatrists and geriatric consultation teams

When pharmacological or non-pharmacological delirium treatments are initiated, CAM-S quantifies the degree of symptomatic response, providing objective data to guide medication titration or alternative strategies.

Prognosis and Outcome Prediction

Geriatricians and palliative care teams

Higher cumulative CAM-S scores during hospitalisation predict worse outcomes including longer stay, greater functional decline, nursing home placement, and mortality, informing goals-of-care discussions.

Pro Tips

CAM-S Requires a Preceding CAM Diagnosis

Do not use CAM-S to diagnose delirium — it is not designed for this purpose. The CAM four-feature diagnostic algorithm determines whether delirium is present; CAM-S then grades its severity. Applying CAM-S without a CAM diagnosis is methodologically incorrect.

Short Form for Clinical Use, Long Form for Research

The CAM-S short form (0–7) is practical for daily clinical monitoring and is validated for predicting outcomes. The long form (0–19) provides more granular severity detail and is preferred for research endpoints. Use the form that matches your clinical or research purpose.

Cumulative Severity Burden Predicts Outcomes Better Than Peak Score

Research shows that cumulative CAM-S burden (area under the severity curve across days) is a stronger predictor of functional decline and mortality than peak or admission score. Track and document scores each assessment cycle.

Score During the Period of Maximum Impairment

Delirium fluctuates. CAM-S assessed during a lucid interval may dramatically underestimate actual burden. Score during observed periods of confusion when possible, and use caregiver/nurse observations from the full preceding interval.

Pair With Sleep-Wake Cycle Documentation

CAM-S severity often worsens at night (sundowning). Document time of assessment and sleep-wake patterns alongside scores. This contextual data strengthens the interpretability of serial severity measurements.

Altered Level of Consciousness Is the Most Prognostically Significant Feature

Of the four short-form features, altered level of consciousness (RASS other than alert) carries the highest prognostic weight. Patients with high alertness disturbance scores have consistently worse outcomes in validation studies.

Train Raters to Standardise Feature Definitions

Inter-rater reliability in CAM-S depends on consistent application of feature definitions. Regular training, case review sessions, and clear rating anchors improve reliability across nursing shifts and clinical teams.

Use CAM-S to Guide Discharge Timing

Persistent high CAM-S scores at the time of discharge planning suggest ongoing delirium burden and heightened risk of post-discharge adverse events. Consider delaying discharge or arranging intensive community monitoring for patients with unresolved severity.

Common Questions About Your Results

Evidence-Based Methodology

CAM-S has validation evidence as a practical delirium severity metric linked to clinical outcomes.

Clinical Content Trust

Last reviewed:: April 21, 2026
Guideline version:: Delirium Severity Tracking Review 2026.04
Source set version:: CAM-S source set v1

How to Interpret Your Result

Higher CAM-S totals indicate greater delirium symptom burden and support intensified monitoring/management.

When to Use This Tool

Use when delirium severity tracking is needed in inpatient or consultation settings.

Limitations

Scoring reliability depends on trained assessors and consistent application of CAM feature definitions.

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.

Sources

Changelog

April 21, 2026 · v1.0.0
Added CAM-S severity tool metadata with baseline changelog and review/version fields.

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