Frequently Asked Questions on Pulse Oximeters


What is a pulse oximeter?

A pulse oximeter is a small, lightweight device that monitors the amount of oxygen transmitted into the body. It also determines the pulse rate. Pulse oximeter is a convenient and painless method of keeping an eye on a person’s arterial oxygen saturation and heart rate.

What are pulse oximeters used for?

Pulse oximeters provide regular observation and monitoring of the oxygen saturation of haemoglobin in arterial blood. These devices are generally used in hospitals, medical clinics, operating rooms as well as in homes for patients suffering from asthma, COPD (chronic obstructive pulmonary disease) and congestive heart failure. Individuals with serious respiratory issues should have their SpO2 (or saturation of peripheral oxygen) level checked on a regular basis.

How does a pulse oximeter work?

A pulse oximeter just needs to be clipped on to your fingertip. The probe passes two types of light through the finger – infrared and red. These are transmitted from the probe through the body and into a light detector on the other side. If the haemoglobin is saturated with oxygen then it will absorb more of the infrared light and if there is less oxygen then more of the red light will be absorbed. This is converted into a digital value which is displayed on the pulse oximeter’s screen.

How to read a pulse oximeter?

The number displayed on a pulse oximeter reflects the percentage of haemoglobin saturated with oxygen. Pulse reading in high 90s - from 96% SpO2 through 99% SpO2 - is considered normal. SpO2 reading of 92% or lower is considered as low blood oxygen supply. This indicates hypoxia and requires immediate attention.