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AIR score (Appendicitis Inflammatory Response)

A 0-to-12 score including CRP and peritoneal-irritation intensity to classify suspected acute appendicitis as low, indeterminate or high probability.

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Check the population, units and version. The result shows the formula or classification; it does not make an automatic treatment decision.

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Method · Limits of application

AIR by Andersson (2008), with Tables 2 and 7 corrected by the 2012 erratum: seven components, total 0–12, CRP in mg/L; original groups 0–4, 5–8 and 9–12. The lower-cutoff change proposed in 2021 has not been applied.

The 2008 AIR was studied in people admitted with suspected appendicitis; part of the cohort remained in the indeterminate group and required further investigation. Only the abstract of the original 2008 article was read. The 2012 erratum was read directly: its Tables 2 and 7 correct CRP concentrations and document the points, units and original groups. The numerical check is limited to summing the seven already selected components; it does not approve clinical groups or diagnostic, imaging or surgical decisions. The 2021 revision proposed low risk at a score <4, distinct from the original 0–4 group; that change has not been applied in this edition. Minimum age, exclusions and the complete protocol were not confirmed by reading the 2008 abstract. Unobserved findings must not be treated as absent. Independent professional clinical and language review and authorization of instrument rights have not been performed.

Conditions of use

Check the population, units, inclusion and exclusion criteria, and version in the original source. A result alone does not establish a diagnosis, discharge decision or prescription.

Documented parameters

Vomiting
Right iliac fossa pain
Rebound tenderness or muscular guarding
Temperature ≥ 38.5 °C
Neutrophils
White blood cells
C-reactive protein

3/3 reference cases checked. Numerical tests are not clinical validation.

Sources and documentation

Documented formula

Transcribed from the source or a recorded revision; this is not a clinical recommendation.

Vomiting (1) + right iliac fossa pain (1) + mild (1), moderate (2) or severe (3) peritoneal irritation + temperature ≥38.5 °C (1) + neutrophils 70–84% (1) or ≥85% (2) + leukocytes 10,000–14,900 (1) or ≥15,000 (2) + CRP 10–49 (1) or ≥50 mg/L (2). Total 0 to 12.

References

Identifier: escore-air-apendicite

Original clinical content: Brazilian Portuguese.

Method version

escore-air-apendicite@native-2026-10-03+c4cc43ad97bd

Source for the active edition

The bibliographic edition identifies the source. By itself, it proves neither full conformity of the formula nor clinical approval.

Synthetic cases checked (3)

Synthetic cases for checking the implementation, with no patient data.

Case 1

reference-001

Inputs

Right iliac fossa pain: Yes
Rebound tenderness or muscular guarding: Mild
Neutrophils: < 70%
White blood cells: 10,000 to 14,900/mm³
C-reactive protein: < 10 mg/L
Vomiting: No
Temperature ≥ 38.5 °C: No

{
  "dor": true,
  "defesa": "1",
  "neut": "0",
  "leuco": "1",
  "pcr": "0",
  "vomito": false,
  "temp": false
}

Expected result

{
  "score": 3,
  "level": "low"
}

Actual result

{
  "score": 3
}

Case 2

reference-002

Inputs

Vomiting: Yes
Right iliac fossa pain: Yes
Rebound tenderness or muscular guarding: Moderate
Neutrophils: 70 to 84%
White blood cells: < 10,000/mm³
C-reactive protein: 10 to 49 mg/L
Temperature ≥ 38.5 °C: No

{
  "vomito": true,
  "dor": true,
  "defesa": "2",
  "neut": "1",
  "leuco": "0",
  "pcr": "1",
  "temp": false
}

Expected result

{
  "score": 6,
  "level": "mid"
}

Actual result

{
  "score": 6
}

Case 3

reference-003

Inputs

Vomiting: Yes
Right iliac fossa pain: Yes
Rebound tenderness or muscular guarding: Intense
Temperature ≥ 38.5 °C: Yes
Neutrophils: ≥ 85%
White blood cells: ≥ 15,000/mm³
C-reactive protein: < 10 mg/L

{
  "vomito": true,
  "dor": true,
  "defesa": "3",
  "temp": true,
  "neut": "2",
  "leuco": "2",
  "pcr": "0"
}

Expected result

{
  "score": 10,
  "level": "high"
}

Actual result

{
  "score": 10
}

Code and reproducibility

This tool’s code on GitHub

Download code and tests

Sources, version and reproduction instructions

The code tests are technical checks. Clinical approval and professional translation review are recorded separately.

Relationship with cancer research

General context — relationship to be defined

A resource for general clinical contexts. This edition does not assign a specific oncological relationship; selecting it for a study requires a justified question, population and purpose.