A pulse oximeter is a small device that fits on your finger and quickly and easily checks your oxygen levels and heart rate.
On this page, you can find the following information:
- What is a pulse oximeter?
- When should I use a pulse oximeter?
- How do I use a pulse oximeter?
- What do pulse oximeter numbers mean?
- Other signs or symptoms of low oxygen levels
- Limitations in using pulse oximeters
What is a pulse oximeter?
Image: Health Navigator NZ
A pulse oximeter is a small, painless device that clips onto your finger and uses light beams in a sensor to estimate the amount of oxygen in your blood without taking a blood sample. This helps to track and assess how well your lungs are working.
Note: Be aware that the quality and accuracy of different pulse oximeters can vary.
A pulse oximeter measures 2 things:
- Pulse – this is a measure of how fast your heart is beating. Your pulse is measured in beats per minute (bpm). On your device this number may show as bpm or PRbpm (pulse rate/beats per minute).
- Oxygen saturation level – this is a measure of how much oxygen is in your blood. Your oxygen saturation is measured as a percentage (scored out of 100). On your device this number may show as SpO2% (saturation percentage of oxygen).
When should I use a pulse oximeter?
A pulse oximeter can be used to help monitor a range of conditions in hospital or at home, including COVID-19 infection. COVID-19 is a viral infection. For most people, the symptoms are relatively mild, and they usually get better over 2–3 weeks. However, for some people, the symptoms can be very serious and can get worse quickly.
- Your healthcare team will let you know if you need a pulse oximeter at home
- If you are advised to monitor your symptoms and breathing, then the use of a health and symptom diary can help you and your healthcare team track any changes.
This page will explain how to use a pulse oximeter, what the numbers mean and what actions you should take.
If at any time you experience shortness of breath at rest or difficulty breathing, or your symptoms become suddenly worse, call 111 for an ambulance. |
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How do I use a pulse oximeter?
There are different brands of these devices – please read the manufacturer's instructions. The following video and table provides a general guide. Ask your healthcare team if you have any questions.
Click the image below to play the video:
(Health Navigator NZ and Aotearoa Collaborative, NZ, 2021)
View transcript
You can also watch this video directly on Youtube.
How to use a pulse oximeter – a general guide |
Preparing
Taking your reading
Recording your numbers
|
What do pulse oximeter numbers mean?
Your healthcare team will give you details on appropriate oxygen saturation levels for your specific medical condition. The following is a guide for adults with no previous lung conditions.
Oxygen saturation SpO2% |
Pulse rate (bpm or PRbpm) | Action |
95–100 | 50–99 | ✔ Acceptable |
92–94 | 100 –119 | Seek advice from your COVID-19 healthcare team |
Below 92 | 120 or more | Call 111 for urgent medical care |
Other signs or symptoms of low oxygen levels
Do not rely only on a pulse oximeter to assess your health condition or oxygen level. It is only a measurement device.
Other signs or symptoms of low oxygen levels are:
- bluish colouring in your face, lips or nails
- shortness of breath, difficulty breathing or a cough that gets worse
- restlessness and discomfort
- chest pain or tightness
- fast or racing pulse rate.
If you have any concerns or questions, contact your healthcare team directly.
If at any time you experience any of the symptoms above, or your symptoms become suddenly worse, call 111 for an ambulance. |
Limitations in using pulse oximeters
Pulse oximeters are very useful devices but it is important to remember that there are limitations to their use.
- Be aware that lots of different factors can affect the accuracy of a pulse oximeter reading. These include poor circulation, skin pigmentation/colouring, skin thickness, skin temperature, current tobacco use, use of fingernail polish or artificial nails, tattoos and dyes, and maintenance and cleaning of devices.
- Also be aware not all pulse oximeters are of the same quality and accuracy.
If you have any breathing problems or concerns, phone your healthcare team or HealthLine 0800 611 116 for advice. Do not rely on a pulse oximeter alone to assess your health condition or oxygen level, it is only a measurement device.
Learn more
Pulse oximetry British Lung Foundation, UK
References
- Pulse oximetry American Thoracic Society, US
- Pulse oximeter accuracy and limitations Food and Drug Administration, US
- Remote management of covid-19 using home pulse oximetry and virtual ward support British Medical Journal, 2021
- Limitations of pulse oximeters and the effect of skin pigmentation Therapeutics Goods Administration, Australia
- The use and regulation of pulse oximeters (information for healthcare professionals) Medicines and Healthcare products Regulatory Agency (MHRA), UK
- Pulse oximeter accuracy and limitations FDA, US