APACHE II Score — Free Online Calculator
Physiological Variables
Age & Chronic Health
APACHE II Score
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About This Calculator
The APACHE II (Acute Physiology and Chronic Health Evaluation II) scoring system is used to estimate ICU mortality risk. It is calculated from 12 physiological variables measured within the first 24 hours of ICU admission, plus age and chronic health status. Higher scores indicate greater severity of illness and higher predicted mortality.
Formula
Interpretation
| APACHE II Score | Approximate Mortality |
|---|---|
| 0 – 4 | ~4% |
| 5 – 9 | ~8% |
| 10 – 14 | ~15% |
| 15 – 19 | ~25% |
| 20 – 24 | ~40% |
| 25 – 29 | ~55% |
| 30 – 34 | ~73% |
| ≥ 35 | ~85% |
References
Frequently Asked Questions
When should the APACHE II score be calculated?
APACHE II uses the worst values from the first 24 hours of ICU admission. It should be calculated once using the most deranged physiological values during this initial period, not on subsequent ICU days.
What does the chronic health component include?
Severe organ insufficiency or immunocompromised state (chronic liver disease, NYHA Class IV heart failure, dialysis-dependent renal failure, immunosuppression) adds 5 points for nonoperative or emergency surgical patients, or 2 points for elective surgical patients.
Is APACHE II still used in modern ICUs?
Yes, APACHE II remains one of the most widely validated and cited ICU scoring systems. While newer versions (APACHE III, IV) and other scores (SAPS, SOFA) exist, APACHE II is still commonly used for research and benchmarking due to its extensive validation across diverse populations.
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⚠ Medical Disclaimer
This tool is for educational and informational purposes only. It is not intended to replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare professional for clinical decisions.