Dismiss Modal

Diagnosis

Pulse Oximetry

Choose a preferred language


What is pulse oximetry?

Pulse oximetry is a test used to measure the oxygen level (oxygen saturation) of the blood. It's an easy, painless measure of how well oxygen is being sent to parts of your body furthest from your heart, such as the arms and legs.

A clip-like device called a probe is placed on a body part, such as a finger or ear lobe. The probe uses light to measure how much oxygen is in the blood. This information helps the doctor decide if a person needs extra oxygen.


Why might I need pulse oximetry?

Pulse oximetry may be used to see if there is enough oxygen in the blood. This information is needed in many kinds of situations. It may be used:

  • As part of a routine wellness check.
  • During or after surgery or procedures that use sedation.
  • To see how well lung medicines are working.
  • To check a person's ability to handle increased activity levels.
  • To see if a ventilator is needed to help with breathing, or to see how well it's working.
  • To check a person who has moments when breathing stops during sleep (sleep apnea).

Pulse oximetry is also used to check the health of a person with any condition that affects blood oxygen levels, such as:

  • Heart attack
  • Heart failure
  • Chronic obstructive pulmonary disease
  • Anemia
  • Lung cancer
  • Asthma
  • Pneumonia

Your doctor may have other reasons to advise pulse oximetry.


What are the risks of pulse oximetry?

All procedures have some risks. The risks of this procedure may include:

  • Incorrect reading if the probe falls off or is not fully attached to the earlobe, toe, or finger
  • Incorrect reading if there is dark nail polish or artificial nails.
  • Incorrect reading due to skin coloring (pigmentation). Pulse oximetry may miss low oxygen saturations when used on darker skin. Talk with your doctor about the accuracy of your results if you have darker skin.
  • Skin irritation from adhesive (if used) on the probe

Your risks may vary depending on your general health and other factors. Ask your doctor which risks apply most to you. Talk with them about any concerns you have.


How do I get ready for pulse oximetry?

Your doctor will explain the procedure to you. Make sure to ask any questions you have about the procedure. If a finger probe is to be used, you may be asked to remove fingernail polish.

Your doctor may have other instructions for getting ready.


What happens during pulse oximetry?

You may have your procedure as an outpatient. This means you go home the same day. Or it may be done as part of a longer stay in the hospital. It depends on your condition and your doctor's methods. In most cases, pulse oximetry will follow this process:

  1. A clip-like device called a probe will be placed on your finger or earlobe. Or a probe with sticky adhesive may be placed on your forehead or finger.
  2. The probe may be left on for ongoing tracking.
  3. The oxygen probe may be left on while you walk to see if your oxygen falls.
  4. Or it may be used to take a single reading. The probe will be removed after the test.


What happens after pulse oximetry?

You can go home after the test, unless you are in the hospital for another reason. You may go back to your normal diet and activities as instructed by your doctor. Your doctor may give you other instructions after the procedure.


Next steps

Before you agree to the test or procedure make sure you know:

  • The name of the test or procedure
  • The reason you are having the test or procedure
  • What results to expect and what they mean
  • The risks and benefits of the test or procedure
  • What the possible side effects or complications are
  • When and where you are to have the test or procedure
  • Who will do the test or procedure and what that person's qualifications are
  • What would happen if you did not have the test or procedure
  • Any alternative tests or procedures to think about
  • When and how will you get the results
  • Who to call after the test or procedure if you have questions or problems
  • How much you will have to pay for the test or procedure

© 2000-2026 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.

Make an Appointment

Make an Appointment

Find a Doctor

Find a Doctor

Find a Location

Find a Location
Related Articles
Read article
Lung Health
Sleep Study

A sleep study is a number of tests done at the same time during sleep. The tests measure specific sleep characteristics and help to diagnose sleep disorders. Read on to learn what to expect.

Read article
Lung Health
Chest X-Ray

A chest X-ray is an imaging test that uses X-rays to look at the structures and organs in your chest. It can help your doctor see how well your lungs and heart are working.

Read article
Lung Health
CT-Guided Lung Biopsy

Learn about CT-guided lung biopsy, a procedure to collect small tissue samples from an abnormal area in your lung.

Read article
Lung Health
CT Scan of the Chest

A computed tomography (CT) scan is a type of imaging test. It uses X-rays and a computer to make images or slices of the body. A CT scan can make detailed pictures of any part of the body, including the bones, muscles, fat, organs, and blood vessels. They are more detailed than regular X-rays.