Delirium Risk Assessment Calculator
CAM diagnostic algorithm with predisposing and precipitating risk factors for hospital delirium assessment.
About this calculator
This calculator implements the Confusion Assessment Method (CAM), the standard bedside diagnostic algorithm for delirium: a patient screens CAM-positive only when acute onset with a fluctuating course AND inattention are both present, together with either disorganized thinking OR an altered level of consciousness. First published by Inouye and colleagues in 1990, the CAM has been validated across many subsequent studies with pooled sensitivity around 94% and specificity around 89% for detecting delirium against a full psychiatric evaluation as the reference standard. The 0-7 delirium severity score this calculator also reports is NOT the published CAM-S instrument (Inouye et al., Ann Intern Med 2014), which is a separately validated severity measure with its own defined short-form scoring -- this calculator's severity figure is its own construction (the 4 CAM features plus 2 ad-hoc modifiers) that happens to share the same 0-7 range.
Separately, the calculator layers a predisposing risk score (age, prior cognitive impairment, prior delirium history, sensory impairment, illness severity) and a precipitating risk score (medication count, recent surgery, physical restraints, bladder catheter, active infection) into a combined 0-100 risk figure -- this combined score and its length-of-stay and mortality-multiplier estimates are this calculator's own synthesis based on the general literature on delirium risk factors, not a separately validated composite instrument in its own right. Patient age and total medication count, while real predisposing and precipitating risk factors in that combined score, have no effect at all on whether a patient screens CAM-positive, since CAM positivity is determined purely by the four bedside observation items regardless of the patient's age or medication list. What it does not account for: delirium subtype (hyperactive, hypoactive, or mixed), medication review for specific deliriogenic drugs by name, or the fact that CAM requires trained-rater administration to achieve its published accuracy.
Medical Disclaimer
This calculator is for informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions about your health. Never disregard professional medical advice or delay seeking it because of results from this tool.
Inputs
Results
CAM positive (0/1)
0
Figures current as of 1990. Source: Inouye SK, van Dyck CH, Alessi CA, Siegal AP, Horwitz RI. Clarifying confusion: the confusion assessment method. A new method for detection of delirium. Ann Intern Med. 1990;113(12):941-948.
How to Use This Calculator
- Enter the four CAM features (acute onset/fluctuation, inattention, disorganized thinking, altered consciousness) if assessed at the bedside.
- Enter predisposing factors (age, prior cognitive impairment, prior delirium, vision/hearing impairment, severe illness) and precipitating factors (medication count, recent surgery, restraints, catheter, infection).
- Review the CAM positive/negative result and the combined Delirium Risk Score and Risk Category (low, moderate, high, very high).
- Check modifiable risk factors highlighted in the output to prioritize prevention interventions.
- Use the score to initiate the Hospital Elder Life Program (HELP) protocol for high-risk patients.
What each input means
- Acute Onset/Fluctuation
- CAM Feature 1: Acute change in mental status with a fluctuating course?
- Inattention
- CAM Feature 2: Difficulty focusing attention (easily distracted, trouble keeping track of conversation)?
- Disorganized Thinking
- CAM Feature 3: Thinking disorganized or incoherent (rambling, irrelevant conversation)?
- Altered Consciousness
- CAM Feature 4: Level of consciousness anything other than alert (vigilant, lethargic, stupor, coma)?
- Patient age
- Patient age. Risk increases significantly after 65, 70, and 80.
- Prior Cognitive Impairment
- History of dementia or cognitive impairment.
- Prior Delirium History
- Previous episode of delirium.
- Vision/Hearing Impairment
- Significant vision or hearing impairment.
- Severe Acute Illness
- High illness severity.
- Total medications
- Total number of medications. >= 6 is a significant risk factor.
- Recent Surgery
- Surgery within past 48 hours.
- Physical Restraints
- Currently physically restrained.
- Bladder Catheter
- Indwelling urinary catheter in place.
- Active Infection
- Current infection (UTI, pneumonia, etc.).
What each result means
- CAM positive (0/1)
- 1 = Delirium present (meets CAM diagnostic criteria), 0 = Not met.
- Delirium severity score (0-7)
- This calculator's own 0-7 severity score (4 CAM features + 2 ad-hoc modifiers) -- not the published CAM-S instrument, despite the shared range.
- Predisposing risk score
- Score from baseline risk factors (age, cognition, sensory, illness severity).
- Precipitating risk score
- Score from acute triggers (medications, surgery, restraints, infection).
- Combined risk score (0-100)
- Overall delirium risk combining predisposing and precipitating factors.
- Risk category (1-4)
- 1 = Low, 2 = Moderate, 3 = High, 4 = Very high.
- Est. LOS impact (days)
- Estimated additional hospital length of stay from delirium risk.
- Mortality risk multiplier
- Estimated mortality risk multiplier compared to baseline (1.0 = no increase).
How this is calculated
Worked example, using the default values
- Identify Input Parameters14 parametersAcute Onset/Fluctuation = 0, Inattention = 0, Disorganized Thinking = 0, Altered Consciousness = 0 = 14 input(s) provided
- Calculate CAM positiveCAM positive0 = 0
- Calculate Delirium severity scoreDelirium severity score0 = 0
- Calculate Predisposing risk scorePredisposing risk score2 = 2
Figures and sources
- Confusion Assessment Method (CAM) delirium diagnostic algorithm (1990) — Inouye SK, van Dyck CH, Alessi CA, Siegal AP, Horwitz RI. Clarifying confusion: the confusion assessment method. A new method for detection of delirium. Ann Intern Med. 1990;113(12):941-948.
Engine last updated . Checked against 3 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
What exactly makes a patient screen CAM-positive in this calculator?
CAM positivity requires two features to both be present -- acute onset with a fluctuating course, and inattention -- combined with at least one of two additional features, disorganized thinking or an altered level of consciousness. All other inputs on this page, including age, prior cognitive impairment, and every precipitating factor like recent surgery or infection, feed into the separate combined risk score but have zero effect on whether the patient screens CAM-positive itself, since the original CAM algorithm published by Inouye and colleagues in 1990 defines positivity purely from those four bedside-observed features.
How accurate is the CAM at detecting delirium?
Pooled results across validation studies put CAM sensitivity around 94% and specificity around 89% against a full psychiatric or geriatric evaluation as the reference standard, making it one of the most extensively validated bedside delirium screening tools in clinical use. Accuracy depends heavily on rater training, though -- the CAM was designed for brief, structured administration by trained clinical staff, and informal or untrained use tends to produce lower real-world accuracy than the published validation figures.
Is the combined 0-100 risk score as well-validated as the CAM diagnostic result?
No, and that distinction matters -- the CAM positive/negative result is a validated diagnostic algorithm with published sensitivity and specificity from decades of research, while the combined 0-100 risk score, length-of-stay estimate, and mortality-risk multiplier are this calculator's own synthesis of general delirium risk-factor literature, not a separately validated instrument. Use the CAM result for the diagnostic question and treat the combined score as a rough prioritization aid for prevention efforts, not a clinical-grade risk prediction.
Does taking six or more medications automatically mean a patient screens CAM-positive?
No -- medication count only contributes to the separate precipitating risk score, adding 3 points at six or more medications, and has no bearing on the CAM diagnostic result at all, which depends solely on the four bedside observation features. A patient on ten medications with none of the four CAM features present screens CAM-negative in this calculator, even though that same medication count meaningfully raises their combined risk score for future delirium episodes.
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