Alveolar–Arterial O₂ Gradient

Oxygenation defect assessment.

A–a gradient

Patient parameters

Adjust values, then click Calculate.

FiO₂

21–100

PaCO₂

15–100

PaO₂

30–500

Results

Alveolar–Arterial O₂ Gradient: 4.9 mmHg

What this calculator does

Alveolar–Arterial O₂ Gradient helps you estimate oxygenation defect assessment. The result is computed instantly in your browser and is intended for clinicians, students, and informed patients reviewing screening values.

Formula and variables

Displayed formula: A–a gradient

The engine evaluates: Alveolar–Arterial O₂ Gradient (mmHg). Variable names match the input field keys so you can trace each step from entry to output.

How to use this tool

1. Open the Alveolar–Arterial O₂ Gradient and enter your values using the units shown beside each field.
2. Review that inputs are within the typical physiological range before you calculate.
3. Read the result together with the interpretation notes below and your local clinical context.

How to interpret the result

Compare the calculated value with established reference intervals for your population. A single number rarely defines management—combine it with symptoms, trends over time, medications, and physical examination. If the result is unexpected, repeat the calculation with verified inputs before acting on it.

Limitations and disclaimer

This tool supports education and clinical triage only. It does not replace professional medical advice, diagnosis, or treatment. Reference ranges vary by laboratory, age, pregnancy status, and comorbidity. Always confirm critical decisions with institutional protocols and qualified clinicians.