Oxygen saturation in arterial blood (SaO₂) measured via pulse oximetry or blood gas analysis

Why is this test done?

Your healthcare provider may order this test if you have symptoms like shortness of breath, fatigue, or a history of lung diseases (e.g., COPD, asthma). It’s also used during surgeries, anesthesia, or in critical care settings to monitor oxygen levels in real time.

How is the test performed?

A small sensor is placed on your finger, toe, or ear lobe to measure oxygen saturation. Alternatively, blood may be drawn from an artery (arterial blood gas) for more detailed results, though this is less common for routine SaO₂ checks.

What does a low or high result mean?

Low SaO₂ (below expected range) may indicate poor lung function, anemia, or conditions like pneumonia or heart failure. High SaO₂ (above expected range) is rare but could suggest certain blood disorders or technical errors in measurement.

Common conditions affecting results

Conditions like chronic obstructive pulmonary disease (COPD), sleep apnea, or anemia can lower SaO₂. Conversely, certain medications (e.g., nitroglycerin) or high altitudes may temporarily raise it. Always discuss your symptoms and medications with your provider.