Are Pulse Oximeters Accurate?

Perhaps the best place to start is to explain what a pulse oximeter is and how it works.

A pulse oximeter measures the amount of oxygen in your blood. Technically, it measures the oxygen saturation level or SpO2, which should be between 95% and 99%.1

It’s a small device that usually clips onto your finger and passes light through one side of your finger onto a light detector on the other side. As it passes through your finger, the light hits your blood cells and reacts differently to the cells carrying oxygen, compared to the cells not carrying oxygen. Basically, it measures the colour of blood, which is brighter red when there is more oxygen in it.2

Sophisticated technology inside the pulse oximeter then calculates and displays the SpO2 or oxygen level.

If you’re looking to purchase a pulse oximeter for home use, the best advice would be to buy a device from a reputable Australian supplier. That’s because devices sold here are required to be listed in the Australian Register of Therapeutic Goods (ARTG). In order to be included in this TGA Register, the device must meet current minimum “state of the art” design and performance standards. The Heart Sure A320 Pulse Oximeter is the #1 Pulse Oximeter Brand in Australian Pharmacy.3

Things are slightly different in the US, there are two levels of pulse oximeters – prescription grade and OTC grade (Over The Counter). Prescription grade devices are tested by the FDA (The Federal Drug Administration), the equivalent of our TGA. The OTC grade models are not tested, so accuracy is unknown. It is always best to buy local and ensure that the device you are purchasing meets the minimum standards in your country.

However, even with a reputable device such as the Heart Sure A320, there are some precautions you should take to ensure you’re getting an accurate reading each time.

According to the American Thoracic Society, accuracy can be impacted by the following conditions:5

  • Your hands are cold
  • You are not sitting still enough
  • You are wearing nail polish (especially black, blue or green)
  • You are wearing artificial nails
  • Your oxygen saturation is very low (below 80%)
  • Your skin is thicker than normal
  • Skin pigment can also impact the accuracy of pulse oximetry. Recent studies show that in those with darker skin pigments, pulse oximetry may miss below- normal oxygen saturations. If you have dark skin and are worried about low oxygen, talk to your doctor about other ways to assess, especially if you have respiratory symptoms.
  • If you smoke, the reading on your pulse oximeter may be higher than your actual oxygen saturation, because smoking increases carbon monoxide levels in your blood, which interferes with readings

In summary, if you use a pulse oximeter from a reputable company, and avoid the mistakes above, you can feel confident you’re getting an accurate picture of your oxygen levels. Check out the leading Heart Sure device here.

Always read the label and follow the directions for use. Consult your health professional to evaluate the readings.


  1. https://exercise.lovetoknow.com/about-physical-fitness/understanding-blood-oxygen-levels-during-exercise
  2. https://www.theguardian.com/australia-news/2022/jan/20/what-is-a-pulse-oximeter-and-can-i-still-buy-one-in-australia-demand-for-devices-climbs-as-more-people-manage-covid-at-home
  3. *IQVIA™, RMS/Sell Out Service, IQVIA defined Oximeter category market, Total value Sales, 52 weeks to 15th Jan 2022.
  4. https://www.fda.gov/medical-devices/safety-communications/pulse-oximeter-accuracy-and-limitations-fda-safety-communication
  5. https://www.thoracic.org/patients/patient-resources/resources/pulse-oximetry.pdf



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