Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier
WebMD

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started
My Medicine
WebMD

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion
    WebMD

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community
    WebMD

    Community

    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

COPD Health Center

Font Size
A
A
A

COPD Diagnostic Tests: Pulmonary Function, Spirometry, and More

Pulse Oximetry

A pulse oximeter is a simple device used to estimate the percent of oxygen in your blood (SpO2). The oximeter can be clipped on your finger or an ear lobe and provides immediate results. Pulse oximetry is not as accurate as getting the oxygen saturation level from an arterial blood gas test. But it is a quick and easy test for getting oxygen levels. Most doctors try to keep oxygen saturations at 88 percent or better. It is normal for saturation values to vary during exercise, sleep and other activities.

The oximeter relies on the fact that hemoglobin that is carrying oxygen is a different color than hemoglobin that is not carrying oxygen. Blood traveling through a vein after it has delivered oxygen to the body is dark red. Blood in an artery that is still carrying oxygen is bright red. By shining a special light through the skin, the oximeter measures how much light is absorbed by the hemoglobin. It then determines what percent of the hemoglobin is carrying oxygen.

Oximetry can be used to help evaluate low oxygen levels in the blood. It can also help in deciding if there is a need for oxygen therapy. However, in patients with severe COPD, an arterial blood gas test is often preferred for making these decisions. An arterial blood gas test is more accurate and gives more information on the PaCO2 and pH values in the body. Pulse oximetry is very useful for measuring oxygen levels while walking, exercising or during sleep. These measurements can provide important information for deciding the earliest need for oxygen therapy. Pulse oximetry can also help determine how well the oxygen therapy is working. However, pulse oximetry can undervalue oxygen levels. This is especially true if the pulse is rapid and harder to gauge.

If you have your own oximeter, talk with your health care provider to decide how to use it correctly. It is not always a good idea to constantly monitor your oxygen levels with every activity you do. Overuse of an oximeter can lead to unnecessary fear and anxiety.

1 | 2 | 3 | 4 | 5 | 6

Today on WebMD

man talking to his doctor
Check your COPD risk.
woman using inhaler
What is the top cause of this condition?
 
chest x-ray
7 early warning signs.
Senior couple stretching
10 exercises for people With COPD.
 
Bronchitis Overview
Article
Senior woman blowing dandelion
ARTICLE
 
Living With Copd
VIDEO
human lung graphic
Article
 
Energy Boosting Foods
Slideshow
red heart and ekg
Article
 
Living With Copd
Article
Senior couple stretching
Slideshow