What do oxygen saturation levels indicate in the body?

Oxygen saturation levels indicate the percentage of hemoglobin binding sites occupied by oxygen. This measurement is critical for assessing a person's respiratory efficiency and overall oxygen transport capability in the blood. Hemoglobin, the protein in red blood cells, binds to oxygen in the lungs and carries it to the tissues throughout the body. A higher oxygen saturation level reflects better oxygen delivery, which is essential for cellular metabolism and function.

When measuring oxygen saturation, typically done using a pulse oximeter, the values range from 0 to 100%. Normal levels are usually between 95% and 100%. This reading helps healthcare providers determine if a patient is experiencing hypoxemia (insufficient oxygen in the blood) or if there is a need for supplemental oxygen or other interventions. The other choices provided relate to different physiological measurements that do not specifically reflect the amount of oxygen bound to hemoglobin.