SpO2 is measured using a pulse oximeter, a small device that is typically clipped onto a patient’s finger, toe, or earlobe. The device uses light-emitting diodes (LEDs) to shine light through the skin, and sensors to measure the amount of light absorbed by oxygenated and deoxygenated hemoglobin. The pulse oximeter then calculates the SpO2 percentage, which usually ranges from 95% to 100% in healthy individuals.
