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Pulse Oximetry

Pulse Oximetry Pronunciation: Pulse Ox-im-e-tree (pʌls ɒkˈsɪmɪtri)

Definition: Pulse Oximetry is a non-invasive method used to monitor a person’s oxygen saturation (SpO2). The device, a pulse oximeter, measures the percentage of hemoglobin in the blood that is saturated with oxygen.

What is Pulse Oximetry?


Pulse Oximetry is a simple, painless, and quick test used to measure how well oxygen is being sent to different parts of the body, particularly the extremities like the arms and legs. It is often used in critical care settings like hospitals but also has applications in general health monitoring.

Key Facts about Pulse Oximetry:

  • Pulse Oximetry is a common and important clinical tool because it can rapidly detect changes in a patient’s oxygenation status.
  • A pulse oximeter device uses light waves to measure oxygen saturation, by passing light through a translucent part of the patient’s body, usually a fingertip or an earlobe.
  • Normal pulse oximeter readings usually range from 95% to 100%. Values under 90% are considered low and indicate potential hypoxemia, or low blood oxygen levels.
  • Pulse oximeters are used in various healthcare settings and can also be used at home for monitoring purposes.

Pulse Oximetry Usage & Understanding Results

How to use a Pulse Oximeter?

Using a pulse oximeter is simple and non-invasive. Here are the basic steps:

  • Place the sensor (usually a clip or a sticky patch) on a thin part of the patient’s body where light can pass through, such as a fingertip or an earlobe.
  • Turn on the pulse oximeter and wait for it to measure the oxygen saturation.
  • Read the SpO2 and pulse rate on the device’s display.

Understanding Pulse Oximeter Results

The reading on a pulse oximeter includes the percentage of oxygen saturation (SpO2) and the pulse rate. Normal SpO2 readings are typically between 95% to 100%. A reading below 90% is usually considered low and might indicate hypoxemia.

Frequently Asked Questions About Pulse Oximetry

What is a normal pulse oximeter reading?

Normal pulse oximeter readings usually range from 95% to 100% SpO2. A reading below 90% is generally considered low and could be a sign of poor oxygen delivery to the body’s tissues.

Can pulse oximetry detect heart disease?

While pulse oximetry is not a standalone test to diagnose heart disease, low SpO2 readings can be a sign of certain heart conditions, especially those that affect the heart’s ability to oxygenate the blood. Always consult with a healthcare provider for proper diagnosis.


  1. American Lung Association. (n.d.). Pulse Oximetry. Retrieved July 25, 2023, from
  2. Mayo Clinic. (n.d.). Pulse Oximetry. Retrieved July 25, 2023, from
  3. Cleveland Clinic. (n.d.). Pulse Oximetry. Retrieved July 25, 2023, from