Bedside delirium screen. Free with attribution.
CAM (Confusion Assessment Method) is a validated clinical instrument used to assess bedside delirium screen. The instrument contains 4 items.
Source / attribution: Inouye SK et al., Ann Intern Med 1990 (free for clinical/educational use with attribution)
The instrument's primary construct — bedside delirium screen — is operationalized through a fixed set of items, each with a defined response format. This standardisation is what allows CAM scores to be compared meaningfully across clinicians, sites, and studies.
Like all screening or assessment instruments, CAM is a structured aid — not a diagnostic test in isolation. Results should be interpreted alongside history, examination, and clinical context. Where a score crosses an actionable threshold, the next step is typically a more detailed clinical evaluation rather than a definitive diagnosis.
Answer all 4 items below to see your CAM score and interpretation.
All scoring runs in your browser. No data is sent anywhere — close the tab and the answers are gone.
CAM uses weighted summation: each item carries a fixed weight that is added when the response indicates a positive finding.
Scoring notes: The simple total here is a heuristic; the formal CAM algorithm requires items 1 AND 2 plus 3 OR 4. Educational use only.
The cutoffs below are drawn from the published validation literature. Always interpret in clinical context.
| Score range | Band | Interpretation |
|---|---|---|
| 0–1 | Delirium unlikely | Delirium unlikely. |
| 2–2 | Delirium unlikely (need both 1 AND 2) | Need item 1 + 2 plus 3 OR 4 for delirium. |
| 3–4 | Delirium likely (if criteria met) | Likely delirium — confirm criteria pattern. |
This is an illustrative walkthrough, not a real patient. Follow the same four steps with your own answers — or use the live calculator at the top of this page.
Mark each item Yes or No. Each "Yes" adds the item's weight; each "No" adds 0. The example below uses illustrative answers.
| # | Item | Example response | Score |
|---|---|---|---|
| 1 | 1. Acute onset and fluctuating course | Yes | 1 |
| 2 | 2. Inattention | No | 0 |
| 3 | 3. Disorganized thinking | Yes | 1 |
| 4 | 4. Altered level of consciousness | No | 0 |
Add the weights from the items where you marked "Yes" (skip the "No" answers — they contribute 0).
1 + 0 + 1 + 0 = 2
Find the row in the interpretation table whose range contains your total:
Total = 2 falls between 2 and 2 → Delirium unlikely (need both 1 AND 2)
Delirium unlikely (need both 1 AND 2). Need item 1 + 2 plus 3 OR 4 for delirium.
A score is one input alongside history and examination. CAM supports clinical judgment — it does not replace it.
If CAM doesn't fit your context, related instruments in geriatrics include:
| Scale | Measures | Items | Time |
|---|---|---|---|
| Barthel Index | Functional independence in ADLs | 10 | — |
| GDS-15 | Depression screening in older adults | 15 | — |
| Katz ADL | Functional independence in basic ADLs | 6 | — |
| Lawton IADL | Functional independence in instrumental ADLs | 8 | — |
| Timed Up and Go | Mobility and fall risk in older adults | 1 | — |
| APGAR Score | Rapid assessment of newborn at 1 and 5 min | 5 | — |
| ASA Physical Status | Pre-operative health status | 1 | — |
| CHA2DS2-VASc | Annual stroke risk in non-valvular atrial fibrillation | 8 | — |
CAM (Confusion Assessment Method) is a validated instrument that assesses bedside delirium screen. It is designed for clinicians, medical students, evidence-synthesis researchers. The 4 items are combined to produce a total score.
CAM contains 4 items. Item scores are combined with weighted scoring to produce the total. Scores run from 0 to 4, grouped into 3 interpretation bands from ‘Delirium unlikely’ up to ‘Delirium likely (if criteria met)’.
On the CAM (total score 0–4), scores of 3–4 fall in the ‘Delirium likely (if criteria met)’ band — interpreted as: Likely delirium — confirm criteria pattern. The full ladder is: 0–1 — Delirium unlikely: Delirium unlikely.; 2 — Delirium unlikely (need both 1 AND 2): Need item 1 + 2 plus 3 OR 4 for delirium.; 3–4 — Delirium likely (if criteria met): Likely delirium — confirm criteria pattern. A higher score reflects a more severe presentation, and crossing a cutoff is a prompt to step up assessment or care — but these bands are screening thresholds, not diagnoses.
Scores of 0–1 fall in the ‘Delirium unlikely’ band: Delirium unlikely. A low score is reassuring but does not by itself rule out the underlying condition — if symptoms or clinical suspicion persist, reassess over time or use a complementary evaluation rather than relying on the number alone.
CAM is free to use with attribution — clinical, educational, and research use is permitted provided the original source is credited. If you publish results or reproduce the scale, include the citation to the source paper.
Inouye SK et al. Ann Intern Med. 1990;113(12):941-948. This is the original publication for the CAM — the reference to cite when reporting results.
No. CAM is a structured assessment aid, not a diagnostic test. Its proper role is clinical assessment of bedside delirium screen — it standardizes assessment and flags who needs closer evaluation, but the result must be weighed alongside history, examination, and clinical context. When a score conflicts with your clinical impression, clinical judgment takes precedence; treatment decisions should never rest on a screening score alone.
CAM is supported by the following peer-reviewed sources: