How Do You Measure Blood Oxygen Levels?

https://www.nist.gov/how-do-you-measure-it/how-do-you-measure-blood-oxygen-levels If you’ve been to the ER, your primary care doctor or an emergency clinic, you’ve probably seen a medical professional place a small, clip-on electronic device on your finger to get a baseline of your vitals. This small device, called an oximeter or pulse ox, measures your blood oxygen level, which is the percentage of oxygen red blood cells carry in the bloodstream. This measurement is known as oxygen saturation.