What are the uses of pulse oximeter?
A pulse oximeter is a small device used at home and in hospitals to check blood oxygen levels. Here we will discuss some of the most important uses of the pulse oximeter.
- A pulse oximeter is an electronic measuring device (also known as a pulse ox) that is used to measure the saturation or concentration of oxygen present in our blood.
- Some fingertip models also display a perfusion index.
- It is also used to measure pulse rate.
People with breathing problems can use it to keep track of their condition and share the readings with their doctor.
What a Pulse Oximeter Measures
A pulse oximeter is a small clip that fits on a fingertip. It uses light to estimate two things: the oxygen saturation of the blood (SpO2) and the pulse rate. The Mayo Clinic notes that a normal oxygen saturation for a healthy adult is usually 95 to 100 percent. A reading below 90 percent is low and needs medical attention. A single reading is only part of the picture. Your symptoms, your breathing, and your overall health matter more than one number.
How to Use a Pulse Oximeter Correctly
The U.S. Food and Drug Administration (FDA) gives these tips for an accurate reading:
- Sit still and rest for a few minutes before you measure.
- Warm your hands if they are cold, as poor circulation can affect the reading.
- Remove nail polish or artificial nails from the finger you use, as they can block the light.
- Place the clip on a fingertip, and keep the hand warm, relaxed, and held below the level of the heart.
- Wait for the reading to steady before you record it. Take more than one reading over time.
Note that the original guide wrongly tells readers to check their vision level and to hold a hand on the chest for 5 to 10 minutes. The correct step is to rest, warm your hands, and keep the hand still while the device measures. Do not use a pulse oximeter to diagnose yourself. A low reading with breathlessness or chest pain needs emergency care.
When Readings Can Be Wrong
The FDA issued a safety communication in 2021 noting that pulse oximeters may be less accurate in people with darker skin. Other factors can also affect accuracy: nail polish, artificial nails, cold hands, movement, and poor circulation. A reading can also be wrong if the device is not approved as a medical device. The FDA advises people to look for devices that are cleared by the FDA, and to treat readings as one piece of information, not a diagnosis. If your reading does not match how you feel, seek medical care.
| Factor | How It Affects the Reading | What to Do |
|---|---|---|
| Dark skin tone | May read higher than the true value | Watch symptoms, not only the number |
| Nail polish | Blocks the light sensor | Remove polish from the test finger |
| Cold hands | Poor blood flow lowers accuracy | Warm hands before measuring |
| Movement | Causes unstable readings | Sit still until the reading steadies |
Frequently Asked Questions
What is a normal pulse oximeter reading?
For a healthy adult, the Mayo Clinic notes that a normal oxygen saturation is usually 95 to 100 percent. A reading below 90 percent is low and needs medical attention.
How do I use a pulse oximeter correctly?
Sit still, warm your hands, remove nail polish from the test finger, place the clip on a fingertip, and wait for a steady reading. Take more than one reading over time.
Can a pulse oximeter be wrong?
Yes. The FDA notes that readings can be less accurate with darker skin, nail polish, cold hands, or movement. Treat the reading as one piece of information, not a diagnosis.
Should I buy a pulse oximeter from Amazon?
When should I seek care for a low oxygen reading?
Seek emergency care if a low reading comes with breathlessness or chest pain. Do not wait to see if it improves on its own.
Disclaimer: This guide gives general information only. It is not a substitute for medical care. A pulse oximeter does not diagnose illness. Talk to your own doctor about your own readings. This guide gives no medical advice for readers.
Last Updated: 6 November 2026