A
A-a Gradient
Calculate the Alveolar-arterial oxygen gradient to differentiate between pulmonary and extrapulmonary causes of hypoxemia based on ABG results.
ABG & Vitals
Clinical Precision & Methodology
The Alveolar-arterial (A-a) oxygen gradient helps identify the underlying cause of hypoxemia. By comparing the calculated oxygen in the alveoli (PAO2) to the measured oxygen in the arteries (PaO2), clinicians can pinpoint respiratory shunts or diffusion defects.
Alveolar Gas Equation
Calculates PAO2 by adjusting for inspired oxygen concentration, atmospheric pressure, water vapor pressure in the lungs, and arterial carbon dioxide divided by the respiratory quotient.
Age-Adjusted Baseline
Automatically calculates the expected "normal" gradient for the patient's age. The A-a gradient naturally widens as patients age due to physiological changes in the lungs.
Thermal Receipt Export
Generates a high-resolution, perfectly scaled PNG image designed specifically for 80mm thermal printers, enabling instant clinical handouts.
Diagnostic Interpretation
How A-a Gradient Calculator Works
Our high-performance online utility runs entirely client-side, processing your files securely and instantly inside your web browser. For related functions, you can also use our All Medical Tools and BP Analyzer utilities.
Enter ABG Values
Step-by-step interactive processing designed for simple, fast, and high-fidelity execution.
Set FiO2
Step-by-step interactive processing designed for simple, fast, and high-fidelity execution.
Calculate Gradient
Step-by-step interactive processing designed for simple, fast, and high-fidelity execution.
Clinical Application
Designed for professional results, privacy, and maximum compatibility across all modern desktop and mobile browsers:
Alveolar Oxygen
Full digital precision and optimized performance with zero server-side latency or external data transfers.
Arterial Oxygen
Full digital precision and optimized performance with zero server-side latency or external data transfers.
Normal Range
Full digital precision and optimized performance with zero server-side latency or external data transfers.
Hypoxia Cause
Full digital precision and optimized performance with zero server-side latency or external data transfers.