What is pulse oximetry?
Pulse oximetry is a test used to measure the oxygen level (oxygen saturation) of the
blood. It is 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 healthcare provider 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:
- 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 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 (COPD)
- Lung cancer
Your healthcare provider 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 the earlobe, toe, or finger
- Skin irritation from adhesive on the probe
Your risks may vary depending on your general health and other factors. Ask your healthcare
provider which risks apply most to you. Talk with him or her about any concerns you
How do I get ready for pulse oximetry?
Your healthcare provider 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 healthcare provider 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. The way the procedure
is done may vary. It depends on your condition and your healthcare provider's methods.
In most cases, pulse oximetry will follow this process:
- 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.
- The probe may be left on for ongoing monitoring.
- 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 healthcare
provider. Your healthcare provider may give you other instructions after the procedure.
Before you agree to the test or the 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 will you have to pay for the test or procedure