Blood oxygen levels, also known as oxygen saturation or SpO2 (peripheral capillary oxygen saturation), measure the percentage of oxygen bound to hemoglobin in the blood. Hemoglobin is the protein in red blood cells that carries oxygen from the lungs to the rest of the body.
Normal blood oxygen levels typically range from 95% to 100%. If the blood oxygen level falls below 90%, it is considered low (hypoxemia), which can indicate a problem with the lungs or the body’s ability to transport oxygen.
Monitoring blood oxygen levels is crucial in various medical contexts, including during surgery, in intensive care units, for people with respiratory conditions such as chronic obstructive pulmonary disease (COPD), or for those at high altitudes where oxygen levels are lower.
Blood oxygen levels can be measured using a pulse oximeter, a small device that clips onto a finger, earlobe, or toe and uses light to determine the oxygen saturation in the blood. This measurement is often displayed as a percentage on the device.