APACHE II Score Calculator

APACHE II Score Calculator for Critical Care. Higher APACHE II totals generally represent greater measured severity. A total alone is not a diagnosis-adjusted mortality prediction and should not determine treatment limits.

For shared guidance on choosing a tool and documenting results, read the clinical calculator workflow.

How this calculator works

This page accepts an already completed APACHE II total from an authorized assessment. It does not calculate the physiological components, age contribution or chronic-health contribution.

When to use this calculator

To record and discuss an existing APACHE II score in an ICU audit or research context using the specified assessment window and source instrument.

Inputs used

  • Externally completed integer APACHE II total (0-71)

Clinical interpretation

Higher APACHE II totals generally represent greater measured severity. A total alone is not a diagnosis-adjusted mortality prediction and should not determine treatment limits.

Worked example

Entering an externally completed integer total of 20 records 20. It is not possible to reconstruct or verify that total from this page because the underlying observations are not entered here.

Limitations and safety notes

The original worksheet and scoring instructions are not reproduced. Licensing and appropriate source-instrument access must be established independently. A score-entry interface is not a physiological calculator.

Frequently asked questions

Where do I enter blood gases and vital signs?

This component does not provide those fields. Complete the assessment using the authorized instrument before entering the total.

Does the displayed band verify the original assessment?

No. It only categorizes the number entered.

References

  • Knaus WA et al. APACHE II: a severity of disease classification system. 1985. PMID: 3928249. https://pubmed.ncbi.nlm.nih.gov/3928249/

Editorial review and citation methodology

Maintained by the Quick Medical Calculator Editorial Team. Content record date: September 7, 2026. A content date is not evidence of independent clinical review. Individual clinical sign-off is not recorded on this page.

  • Prefer original validation studies for scoring systems and prediction tools.
  • Use current specialty society guidance, transplant allocation policy, public health guidance, or regulator resources when they govern clinical use.
  • Include limitations and safety notes when a calculator is population-specific, context-dependent, or unsuitable as a standalone decision tool.

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