Posted September 30, 2022 by Anusha ‐ 2 min read
Pulse oximetry, or pulse ox, is a quick, inexpensive, and needle-free test that measures the amount of oxygen in your blood. It shows whether your heart and lungs supply enough oxygen to meet your body's needs.
Why Would I Need This Test?
Your doctor will use pulse oximetry whenever they think that your blood-oxygen levels could be too low. The device can help:
Diagnose symptoms like shortness of breath
Track your blood oxygen level during surgery
Test oxygen levels when you use supplemental oxygen
Show if you need extra oxygen when you exercise
Procedure for Pulse Oximetry
You may get this test during a doctor visit or hospital stay.
Your nurse will put a small, clip-like device called a pulse oximeter on your finger, toe, or ear.
Or they’ll put a sticky disposable probe on your finger, nose, toe, or forehead.
The pulse oximeter uses a special type of light to see how much oxygen is in the red blood cells traveling through the blood vessels under your skin.
The test is painless and quick.
In just a few seconds, the device will show your heart rate and oxygen saturation level the percentage of your red blood cells carrying oxygen.
It also measures your heart rate.
Your nurse will take the clip off if it’s just a one-time check.
During surgery or a sleep study, it may stay in place to track your blood oxygen.
You should be able to go home after pulse oximetry, unless you need to stay in the hospital for a procedure or more monitoring.
Your doctor will let you know what happens next and what to do after the test.
What Do the Results Mean?
A blood oxygen level lower than 89% means you may not have enough oxygen in your blood to meet your body’s needs.
This could be because there’s a problem with your heart or lungs.
If your levels are low, you may need to breathe in extra oxygen through a tube.
But a pulse oximeter reading is simply an estimate.
For example, a reading of 90% oxygen saturation on an FDA-approved prescription machine could mean anything from 86% to 94%.
In addition, a number of other things can affect the accuracy of the reading, including:
Long or dirty fingernails
Different pulse oximeter sensors (finger clip vs. adhesive)
Risks of Pulse Oximetry
Pulse oximetry is a safe test. There are no real risks. But:
Sometimes the sticky material on the probe might irritate your skin.
If you or your nurse don’t put the sensor on the right way, you may not get an accurate result.