🫁 Arterial Blood Gas Interpretation (6-Step)
A six-step arterial blood gas interpretation framework — pH, primary disorder, compensation, anion gap, delta/delta and oxygenation. Browser-side reference.
Inappropriate compensation signals a coexisting second disorder.
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When to use
Systematically read an ABG at the bedside; use the dedicated acid-base calculators for the actual numbers.
How it works
① pH → ② primary disorder (PaCO₂ vs HCO₃) → ③ compensation → ④ anion gap → ⑤ delta/delta → ⑥ oxygenation (A-a gradient).
Key points
- Inappropriate compensation signals a coexisting second disorder.
- With a high anion gap, check delta/delta for a mixed picture.
- Use this site's tools for compensation, AG, delta ratio and A-a gradient.
- Always correlate with history, electrolytes and renal function.
References
Worked calculation
The values below come from this tool's own example placeholders and are computed server-side with the formula shown on this page, so the arithmetic can be checked quickly. It demonstrates how to substitute values only — it is not clinical advice and not a real case.
| View | Six steps |
|---|
→InterpretationABG six-step method
- ① pH：< 7.35 acidaemia, > 7.45 alkalaemia (may normalise after compensation)
- ② Primary：See whether PaCO₂ or HCO₃ moves in the same direction as pH
- ③ Compensation：Is compensation appropriate (see 'Acid-base compensation', 'Winter')
| View | Oxygenation |
|---|
→InterpretationOxygenation
- Oxygenation：PaO₂, SaO₂, P/F ratio
- A-a gradient：Elevated = diffusion/shunt/V-Q mismatch; normal = hypoventilation/low inspired O₂ (see 'A-a gradient')
Frequently asked questions
- What is Arterial Blood Gas Interpretation (6-Step)?
- A six-step arterial blood gas interpretation framework — pH, primary disorder, compensation, anion gap, delta/delta and oxygenation. Browser-side reference.
- How is Arterial Blood Gas Interpretation (6-Step) calculated? What is the core formula?
- ① pH → ② primary disorder (PaCO₂ vs HCO₃) → ③ compensation → ④ anion gap → ⑤ delta/delta → ⑥ oxygenation (A-a gradient).
- When is Arterial Blood Gas Interpretation (6-Step) used?
- Systematically read an ABG at the bedside; use the dedicated acid-base calculators for the actual numbers.
- What are the key clinical points for Arterial Blood Gas Interpretation (6-Step)?
- Inappropriate compensation signals a coexisting second disorder. With a high anion gap, check delta/delta for a mixed picture. Use this site's tools for compensation, AG, delta ratio and A-a gradient. Always correlate with history, electrolytes and renal function.
- What are the limits and cautions when using Arterial Blood Gas Interpretation (6-Step)?
- For licensed clinicians and clinical researchers. Interpret results with history, investigations and local protocols; not a diagnosis or prescription, and not a substitute for multidisciplinary decision-making or local guidelines.
- How is Arterial Blood Gas Interpretation (6-Step) calculated in practice? Can you show a worked example?
- Inputs: View Six steps → Result: Interpretation ABG six-step method（① pH: < 7.35 acidaemia, > 7.45 alkalaemia (may normalise after compensation), ② Primary: See whether PaCO₂ or HCO₃ moves in the same direction as pH, ③ Compensation: Is compensation appropriate (see 'Acid-base compensation', 'Winter')） Inputs: View Oxygenation → Result: Interpretation Oxygenation（Oxygenation: PaO₂, SaO₂, P/F ratio, A-a gradient: Elevated = diffusion/shunt/V-Q mismatch; normal = hypoventilation/low inspired O₂ (see 'A-a gradient')）