ABG Interpreter
Enter ABG values. The tool classifies the disorder, checks expected compensation, flags mixed disorders, and suggests teaching points. Education only — not for clinical decision-making.
Inputs
Normal ranges used: pH 7.35–7.45, PaCO₂ 35–45, HCO₃⁻ 22–26. Compensation rules: Winter's formula for metabolic acidosis; 0.7×HCO₃+20±5 for metabolic alkalosis; acute/chronic respiratory changes of 1/3.5 per 10 mmHg CO₂ (acidosis) and 2/4.5 per 10 (alkalosis).
Results
Acid–Base Status
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Primary Disorder
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Compensation Check
Mixed Disorder?
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Oxygenation
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P/F Ratio
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Teaching Notes & Treatment Considerations
Enter values above and click "Interpret ABG" to see educational notes.
How this decides the primary disorder
- Determine
pHdirection (acidemia, alkalemia, or normal). - Test each candidate disorder against its expected compensation:
- **Metabolic acidosis:** expect PaCO₂ ≈
1.5 × HCO₃ + 8 ± 2(Winter's). - **Metabolic alkalosis:** expect PaCO₂ ≈
0.7 × HCO₃ + 20 ± 5. - **Respiratory acidosis:** HCO₃ rises by
+1(acute) or+3.5(chronic) per 10 mmHg CO₂ above 40. - **Respiratory alkalosis:** HCO₃ falls by
−2(acute) or−4.5(chronic) per 10 mmHg CO₂ below 40.
- **Metabolic acidosis:** expect PaCO₂ ≈
- The scenario with the smallest error (
actual vs expected) that matches the pH direction is chosen as primary. If compensation lies outside the expected range, a **mixed disorder** is flagged.