A-a Gradient Calculator
Calculate the alveolar-arterial (A-a) oxygen gradient to evaluate oxygenation and differentiate causes of hypoxemia.
Medical Disclaimer
This calculator is for informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions about your health. Never disregard professional medical advice or delay seeking it because of results from this tool.
Inputs
Results
A-a Gradient
4.7mmHg
Elevated
0(0=No, 1=Yes)
How to Use This Calculator
- Enter FiO₂, PaO₂, PaCO₂, atmospheric pressure, and patient age.
- Review the A-a gradient — normal is < age/4 + 4 mmHg on room air.
- An elevated A-a gradient suggests a parenchymal, vascular, or diffusion lung abnormality.
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