What is the normal arterial oxygen saturation (SaO2) percentage?

The normal arterial oxygen saturation (SaO2) percentage indicates the amount of oxygen that is being carried by hemoglobin in the blood compared to its total capacity for oxygen. A SaO2 of 97% or above is generally considered the normal range for healthy individuals, reflecting efficient oxygen transport and utilization by the body's tissues. This level suggests that the lungs are functioning well and that oxygen from the air is being adequately transferred into the bloodstream.

While values slightly lower than this, such as 90% or 85%, may still be seen in some individuals, they indicate mild to moderate hypoxemia, which may require further assessment or intervention depending on the patient’s condition and overall clinical picture. A saturation of 100% is also possible but is not considered a typical "normal" measurement because it may not account for physiological variations and can sometimes indicate over-oxygenation, particularly in certain clinical scenarios. Consequently, SaO2 readings consistently at or above 97% are the benchmark for evaluating ideal oxygenation in healthy adults.