How to Use a Pulse Oximeter to Check Oxygen Saturation Levels (2024)

Jun 24, 2024

Fact Checked

Pulse oximeters are a quick and painless way to check your blood oxygen levels.

Written by: Lauren Evoy Davis

Medical Reviewer: Elizabeth U. Lyda, RRT

Reviewed by: Susan Stiles, PhD, Senior Director of Healthy Aging Innovations at NCOA

Key Takeaways

  • Finger pulse oximeters provide a quick and painless way to check blood oxygen saturation levels.
  • An ideal oxygen level is between 95% and 100%.
  • Pulse oximetry can help people with respiratory or cardiovascular conditions.
  • The price for a home-use pulse oximetry device ranges from $25 to $100.

For people who use respiratory aids like aCPAP machine, portable oxygen concentrator, or home oxygen concentrator, regularly checking their oxygen saturation is important. Pulse oximeters are devices used to check blood oxygen levels. They’re quick, painless, and can be used at home or in medical settings.

“The pulse oximeter emits light through the skin and measures the oxygen saturation of the arterial blood,” said Chris McDermott, an advanced practice registered nurse at Intercoastal Consulting & Life Care Planning in Jacksonville, Florida. “This information is essential in determining whether an individual is receiving enough oxygen, especially during activities like exercise or sleep,” he added.

Oxygen levels can indicate respiratory and heart health for people with conditions like asthma or chronic obstructive pulmonary disease (COPD). If you’re new to using a pulse oximeter, our step-by-step guide can help you learn best practices, how to read the results, and when to seek help.

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How to use a pulse oximeter

Read the manufacturer’s instructions carefully to see how to use your specific device and if your oximeter needs batteries. Before taking an oximeter reading, make sure your fingernails are dry and clean. Remove any fingernail polish, acrylic nails, or artificial nail tips before proceeding with the following steps:

  1. Warm your hands if they are cold or cool to the touch.
  2. Find a comfortable position and rest for at least five minutes before taking a reading.
  3. Place the oximeter on the fingertip of either your index (pointer) finger or your middle finger. It should feel snug but comfortable.
  4. Keep still for at least a minute. If the numbers keep fluctuating, you may need to be still for longer. Once the numbers remain steady, you have your reading.
  5. Record the two numbers you see. One is your oxygen saturation level, and the other is your heart rate. Each will be clearly labeled on the device.
  6. Remove the device from your finger and store it in a safe place.

Your health care provider may ask you to record your readings, which you can do in a dedicated notebook or an app on your smartphone or tablet. [1]National Health Service. How to Use a Pulse Oximeter at Home. Feb 11, 2021. Found on the internet at https://www.youtube.com/watch?v=tWlv2V-MJU8 Tracking your health trends over time can help your health care team provide the best and most accurate care.

Pulse oximeter readings

Not everyone who uses a pulse oximeter will have the same readings. For example, people with chronic lung conditions or who smoke may have a lower baseline heart rate. [2]Ridgmount Practice. How to Use a Pulse Oximeter at Home. April 29, 2021. Found on the internet at https://www.ridgmountpractice.nhs.uk/pulse-oximeters Pulse oximeters provide only an estimate of oxygen saturation (Sp02). If a U.S. Food and Drug Administration (FDA)-approved pulse oximeter reads 90%, then the actual oxygen saturation in the blood is approximately between 86% and 94%. [3]US Food and Drug Administration. Pulse Oximeter Accuracy and Limitations: FDA Safety Communication. Feb. 19, 2021. Found on the internet at https://www.fda.gov/medical-devices/safety-communications/pulse-oximeter-accuracy-and-limitations-fda-safety-communication

This chart shows the range of readings in blood oxygen levels.

Table 1 Pulse oximeter readings chart

Oxygen saturation

(Sp02%)

Pulse rate

(Beats per minute)

Reading

95%–100%60–100Normal
95%101–109Continue monitoring
93%–94%110–130See your health care provider
92% or lower131 or higherGo to the emergency room or call 911

What factors affect the results?

The FDA recommends telling your health care provider if you use a pulse oximeter at home to ensure you do it correctly. [4]U.S. Food and Drug Administration. Pulse Oximeters and Oxygen Concentrators: What to Know About At-Home Oxygen Therapy. Feb. 19, 2021. Found on the internet at https://www.fda.gov/consumers/consumer-updates/pulse-oximeters-and-oxygen-concentrators-what-know-about-home-oxygen-therapy Following pulse oximeter best practices can help you get the most accurate results.

Appropriate placement is key. The first two fingers on either hand are typically best for readings because they get more blood flow than the ring and pinky fingers, explained Kathy Bendle, RN, who works in emergency departments in the Lawrence Memorial Hospital system around New London, Connecticut.

Movement can make it difficult to get a proper reading, so sit comfortably for a few minutes before using the oximeter. Also, keep your nails clean, clipped, and polish-free. Many types of nail polish and artificial nails can block the infrared light emitted from the device and possibly delay an accurate reading. [5]Yale Medicine. Pulse Oximetry. Found on the internet at https://www.yalemedicine.org/conditions/pulse-oximetry

While you can take your reading to the best of your ability, some circumstances out of your control may still affect your results. In 2021, the FDA issued a safety statement indicating that pulse oximeters may give inaccurate readings depending on a person’s skin tone. [3]US Food and Drug Administration. Pulse Oximeter Accuracy and Limitations: FDA Safety Communication. Feb. 19, 2021. Found on the internet at https://www.fda.gov/medical-devices/safety-communications/pulse-oximeter-accuracy-and-limitations-fda-safety-communication A recent study noted fewer accurate readings among Black patients than white patients. [6]Valbuena VSM, et al. Racial Bias in Pulse Oximetry Measurement Among Patients About to Undergo Extracorporeal Membrane Oxygenation in 2019-2020. Sept. 27, 2021. Found on the internet at https://journal.chestnet.org/article/S0012-3692(21)04065-4/fulltext Another study from 2020 indicated that Black patients with hypoxia (low blood oxygen levels) were more likely to get a normal reading than white patients. [7]Sjoding MW, et al. Racial Bias in Pulse Oximetry Measurement. New England Journal of Medicine. Feb. 23, 2021. Found on the internet at https://www.nejm.org/doi/10.1056/NEJMc2029240 These and other studies demonstrate that more research on pulse oximeters in diverse populations is needed to improve care and device function. [8]Valbuena VSM, et al. Racial and Ethnic Bias in Pusle Oximetry and Clinical Outcomes. Journal of the American Medical Association. May 31, 2022. Found on the internet at https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2792654

Your pulse oximeter may be faulty if it gives consistently inaccurate readings. You can report this issue to MedWatch, the FDA’s medical safety reporting program. [9]U.S. Food and Drug Administration. MedWatch Online Voluntary Reporting Form. Found on the internet at https://www.accessdata.fda.gov/scripts/medwatch/index.cfm MedWatch aims to protect patients and help manufacturers improve products.

Who needs to use a pulse oximeter?

Certain health conditions require people to monitor their oxygen saturation levels. People on supplemental oxygen therapy are likely candidates for home pulse oximeters, as are people with:

  • Asthma
  • Blood clots
  • COPD
  • A history of heart attack
  • Heart disease
  • A history of heart failure
  • Lung cancer
  • Lung disease
  • Pneumonia
  • Sleep apnea

Athletes or people living in high altitudes may also benefit from tracking their oxygen saturation levels, according to a recent study. [10]Dünnwald T, et al. The Use of Pulse Oximetry in the Assessment of Acclimatization to High Altitude. Sensors. Feb. 10, 2021. Found on the internet at https://www.mdpi.com/1424-8220/21/4/1263

When should you call a doctor?

According to Yale Medicine, optimal oxygen saturation levels are between 95% and 100%. [5]Yale Medicine. Pulse Oximetry. Found on the internet at https://www.yalemedicine.org/conditions/pulse-oximetry People with low oxygen levels, called hypoxia, may need medical care immediately.

McDermott explains, “If you are using a pulse oximeter and notice consistently low oxygen saturation levels, or if you experience symptoms such as persistent shortness of breath, rapid breathing, confusion, chest pain, or any other concerning symptoms, it is important to consult a health care professional.”

Where can you purchase a pulse oximeter?

Pulse oximeters can be purchased online at websites like Oxiline. They’re also available at most pharmacies and drugstores. Pulse oximeters generally range in price from $25 to $60.

Bottom line

Knowing your oxygen saturation levels is important for people with respiratory conditions like COPD and emphysema. Pulse oximeters are a quick and painless way to check your levels.

Oxygen levels between 95% and 100% are optimal for most people. If you track your oxygen saturation levels at home, connect with your health care provider to ensure you use the device correctly to get the most accurate readings.

How to Use a Pulse Oximeter to Check Oxygen Saturation Levels (2)

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Frequently asked questions

An over-the-counter pulse oximeter can cost anywhere from $25 to $100. Look for FDA-approved devices.

How often you test may vary depending on your health condition. Ask your health care provider how often to check your levels.

Healthy oxygen levels are approximately 95% to 100%. If your reading is consistently below 95%, seek medical attention.

Yes. Recent research found racial bias in oximeter readings. Studies show that people with darker skin tones sometimes get less accurate readings than those with lighter skin. More research is needed to improve care for all patients.

A pulse oximeter reading of 95 to 100 percent is considered normal for healthy adults.

Have questions about this article? Email us at reviewsteam@ncoa.org.

Sources

  1. National Health Service. How to Use a Pulse Oximeter at Home. Feb 11, 2021. Found on the internet at https://www.youtube.com/watch?v=tWlv2V-MJU8
  2. Ridgmount Practice. How to Use a Pulse Oximeter at Home. April 29, 2021. Found on the internet at https://www.ridgmountpractice.nhs.uk/pulse-oximeters
  3. US Food and Drug Administration. Pulse Oximeter Accuracy and Limitations: FDA Safety Communication. Feb. 19, 2021. Found on the internet at https://www.fda.gov/medical-devices/safety-communications/pulse-oximeter-accuracy-and-limitations-fda-safety-communication
  4. U.S. Food and Drug Administration. Pulse Oximeters and Oxygen Concentrators: What to Know About At-Home Oxygen Therapy. Feb. 19, 2021. Found on the internet at https://www.fda.gov/consumers/consumer-updates/pulse-oximeters-and-oxygen-concentrators-what-know-about-home-oxygen-therapy
  5. Yale Medicine. Pulse Oximetry. Found on the internet at https://www.yalemedicine.org/conditions/pulse-oximetry
  6. Valbuena VSM, et al. Racial Bias in Pulse Oximetry Measurement Among Patients About to Undergo Extracorporeal Membrane Oxygenation in 2019-2020. Sept. 27, 2021. Found on the internet at https://journal.chestnet.org/article/S0012-3692(21)04065-4/fulltext
  7. Sjoding MW, et al. Racial Bias in Pulse Oximetry Measurement. New England Journal of Medicine. Feb. 23, 2021. Found on the internet at https://www.nejm.org/doi/10.1056/NEJMc2029240
  8. Valbuena VSM, et al. Racial and Ethnic Bias in Pusle Oximetry and Clinical Outcomes. Journal of the American Medical Association. May 31, 2022. Found on the internet at https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2792654
  9. U.S. Food and Drug Administration. MedWatch Online Voluntary Reporting Form. Found on the internet at https://www.accessdata.fda.gov/scripts/medwatch/index.cfm
  10. Dünnwald T, et al. The Use of Pulse Oximetry in the Assessment of Acclimatization to High Altitude. Sensors. Feb. 10, 2021. Found on the internet at https://www.mdpi.com/1424-8220/21/4/1263.
How to Use a Pulse Oximeter to Check Oxygen Saturation Levels (3)

Lauren Evoy DavisAuthor

Lauren Evoy Davis is a health journalist with expertise in cancer and other chronic conditions. Lauren holds an MA in Journalism from American University and a BA in English from Elon University. Her work has been published by the American Society of Clinical Oncology, Legacy, Health Central, WebMD, Verywell Health, Patient Power, and Verizon.

How to Use a Pulse Oximeter to Check Oxygen Saturation Levels (4)

Elizabeth U. LydaMedical Reviewer

Elizabeth Lyda, RRT, holds a bachelor of science degree from Empire State College and associate of science degree with a certificate in Respiratory Care from Mansfield State University, and has been a respiratory therapist since 1983. She was named Respiratory Therapist of the Year in 2007 from the University of Rochester and remains licensed in the state of New York.

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How to Use a Pulse Oximeter to Check Oxygen Saturation Levels (2024)

FAQs

How to Use a Pulse Oximeter to Check Oxygen Saturation Levels? ›

Place the oximeter on the fingertip of either your index (pointer) finger or your middle finger. It should feel snug but comfortable. Keep still for at least a minute. If the numbers keep fluctuating, you may need to be still for longer.

How to use a pulse oximeter step by step? ›

How do you use a pulse oximeter?
  1. Be sure your hand is warm.
  2. Sit quietly for a few minutes.
  3. Turn on your oximeter. ...
  4. Keep your nail facing up. ...
  5. Hold your finger still and below the level of your heart.
  6. You'll see results in a few seconds.
Mar 15, 2024

What finger should the pulse oximeter go on? ›

Make sure your hand is warm to the touch. Then rest it on your chest for five minutes. Switch the pulse oximeter on. Then attach the clip of the pulse oximeter to the finger next to your thumb, or your middle finger.

What is a normal reading of a pulse oximeter? ›

For most people, a normal pulse oximeter reading for your oxygen saturation level is between 95% and 100%. If you have a lung disease such as COPD or pneumonia, your normal oxygen saturation level may be lower. Your healthcare provider will let you know what levels are acceptable.

How do I get an accurate pulse oximeter reading? ›

Keep your body still. When the numbers on your device are steady and stop changing, record the levels, date, and time of the reading. Track how they change and tell your doctor if they do. Pulse oximeters are most accurate when blood oxygen saturation is between 90% and 100%.

How do you check oxygen saturation with a pulse oximeter? ›

Place the oximeter on the fingertip of either your index (pointer) finger or your middle finger. It should feel snug but comfortable. Keep still for at least a minute. If the numbers keep fluctuating, you may need to be still for longer.

How long to leave a pulse oximeter on your finger? ›

It works best on your middle or index finger. It should not be used on your ear. The reading takes time to steady. Keep the pulse oximeter in place for at least a minute, or longer if the reading keeps changing.

What are three conditions that can give a false pulse oximetry reading? ›

Excessive motion—shivering, shaking, or other movement—can also cause erroneous readings. Skin temperature and thickness can also reduce the accuracy of pulse pulse oximeters, and whether a person smokes tobacco can affect the device's accuracy.

What is the lowest oxygen level before death? ›

An SpO2 level of 92 percent is considered the lowest clinically acceptable level by established norms of clinical practice at any age, except in cases of chronic lung disease, where it is 88 percent. Death can occur due to hypoxemia at any level less than 88 percent.

What is a normal oxygen level for a 70 year old person? ›

A normal oxygen saturation level is 97-100% but older adults typically have lower levels than younger adults. If an individual is older than 70, a normal oxygen level for elderly adults may be about 95%, which is acceptable. In extreme cases, low oxygen levels can result in hypoxemia or hypoxia.

What is a normal range on a pulse oximeter? ›

It can peak and rise during a run or exercise, reducing and staying low due to certain cardiovascular complications. However, the standard studies suggest that the pr bpm normal range in oximeter in healthy adults is between 60-100 beats per minute.

What is the lowest oxygen level you can live with? ›

People should contact a health care provider if their blood oxygen levels drop below 93%, and they should seek prompt medical care if levels are below 88%. It is also important to seek medical attention when experiencing symptoms of a lack of oxygen, including: Shortness of breath. Chest pain.

Why do I feel short of breath but my oxygen saturation is good? ›

You could possibly be retaining CO2. If this is the case, you could still show high sats but still feel short of breath. In fact, high CO2 will trigger the feeling of shortness of breath long before you are actually low on breath.

What should both numbers be on pulse oximeter? ›

Your oxygen meter shows two numbers. Your oxygen level is labeled SpO2. The other number is your heart rate. For most people, a normal oxygen level is 95% or higher and a normal heart rate is generally below 100.

What is the bottom number on a pulse oximeter? ›

The pulse oximeter measures two distinct things: The first number that comes up is most often the pulse rate. Usually this number is marked by a small heart. The second number that comes up is the level of oxygen in the blood. Both numbers are needed to assess your present levels.

What is a normal oxygen saturation level? ›

A resting oxygen saturation level between 95% and 100% is regarded as normal for a healthy person at sea level.

What is normal pi on an oximeter? ›

PI is a parameter which is calculated as the ratio (AC/DC × 100) of pulsatile arterial blood flow (AC) to non-pulsatile (static) blood flow (DC) in peripheral tissues measured by pulse oximeter. It gives values from 0.02 to 20. Its normal average value is 1.4.

What are the symptoms of low oxygen levels? ›

Hypoxia is low levels of oxygen in your body tissues. It causes symptoms like confusion, restlessness, difficulty breathing, rapid heart rate, and bluish skin. Many chronic heart and lung conditions can put you at risk for hypoxia. Hypoxia can be life-threatening.

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