Pulse Oximetry

Last Updated 05/07/2020

Authors:Michael Canfield, MAEd, RRT; Douglas Masini, RRT, EdD, FCCP; Ian Nathanson, MD, FCCP

About Pulse Oximetry

Key facts about Pulse Oximetry
  • A pulse oximeter measures how much oxygen your red blood cells are carrying.
  • It is a small probe that fits over a thin body part, like a finger or earlobe.
  • The pulse oximeter shines light through the body part to measure blood oxygen level (or saturation). It also measures your heart rate.
  • The display shows a percentage. Higher readings are better. A good reading is 90% to 92%.
  • The reading can help diagnose heart or lung problems that are lowering your oxygen saturation. You may be given extra (or supplemental) oxygen as a result.

A pulse oximeter is an electronic device that measures the saturation of oxygen in your red blood cells. If you have shortness of breath or a known lung or heart condition, your health care provider may use a pulse oximeter.

You can attach a pulse oximeter to your finger, forehead, nose, foot, ear, or toe. You can then reuse it or throw it out. If you’re using a pulse oximeter at home, ask your health care provider before disposing of it because it can be expensive and reusable.

pulse oximetry device

What to expect

A pulse oximeter produces a simple, quick, and safe measure of your body’s oxygen saturation. The device uses no needles and causes no pain. Some hospitals also use disposable tape probes that wrap around your finger, nose, or toe.

You or a health care provider will place the probe on the body part. In the case of a finger pulse oximeter, the device shines light from a cold source through the fingertip. This makes the tip appear red. The pulse oximeter analyzes the light from the other side of the finger. In a few seconds, the oximeter will display your heart rate and oxygen saturation.

Oximeters are typically accurate in most use cases. If you’re wearing dark fingernail polish or long artificial nails, or if your fingers are not clean, the pulse oximeter may not work properly.

Understanding the results

The percentage on the oximeter’s screen shows how much oxygen your red blood cells are carrying. This number helps your doctors, respiratory therapist, and nurses pick the right treatment. It may also help determine if you should receive oxygen therapy.

A good saturation is 90% to 92%. This value differs from a value called the partial pressure of oxygen (PO2), which is measured by taking blood from an artery. (A good PO2 is over 60 to 65). Your health care provider can explain the numbers in light of your health situation.

What are the risks?

Using a pulse oximeter has no known risk when a competent health professional reviews and monitors the values.

Michael Canfield, MAEd, RRT, Primary Medical Associates;
Douglas Masini, RRT, EdD, FCCP, Mercer University School of Medicine;
Ian Nathanson, MD, FCCP, Orlando Regional Medical Center