ROUNDS·
Geriatrics / Critical Care

CAM — Confusion Assessment Method

A bedside algorithm for delirium screening, based on four core features.

1. Acute onset and fluctuating course
2. Inattention
3. Disorganized thinking
4. Altered level of consciousness

What is the CAM?

Developed by Inouye and colleagues, the Confusion Assessment Method is a brief, validated algorithm used to screen for delirium at the bedside without specialized equipment.

How to interpret it

CAM is positive (delirium likely) when features 1 and 2 are both present, AND either feature 3 or feature 4 is also present. All four features should be assessed based on observation and a brief cognitive interaction with the patient.

Why it matters

Delirium is common, under-recognized, and associated with worse outcomes if missed — a quick screen like CAM helps catch it especially in hospitalized older adults and ICU patients.

References

Inouye SK, van Dyck CH, Alessi CA, et al. Clarifying confusion: the confusion assessment method. Ann Intern Med. 1990.

Frequently Asked Questions

What makes CAM positive?

CAM is positive (delirium likely) when features 1 and 2 are both present, AND either feature 3 or feature 4 is also present.

Does CAM diagnose the cause of delirium?

No — it screens for the presence of delirium itself. Identifying the underlying cause requires separate clinical workup.

Is there a version for non-verbal or ICU patients?

Yes — the CAM-ICU is a modified version designed for mechanically ventilated and non-verbal patients in intensive care.