How does Samsung Health measure blood oxygen?

In this brief guide, we will discuss “ How does Samsung Health measure blood oxygen”, what is oxygen saturation, instructions on how to measure oxygen saturation levels in the Samsung Galaxy smartphone, the mechanism behind the measurement and much more.

How does Samsung Health measure blood oxygen?

Samsung health uses the smartphone’s inbuilt sensors to measure blood oxygen levels. Some Samsung smartphones are equipped with the sensor to track heart rate and blood oxygen levels.

What is oxygen saturation?              

SpO2 is the term used for oxygen saturation. Blood carries oxygen to the body. Haemoglobin plays an important role in transporting oxygen in the body as it is exclusively responsible to bind to oxygen molecules. This makes the protein structure exist in 2 states: oxygenated haemoglobin and deoxygenated haemoglobin. The ratio of the oxygen-carrying haemoglobin to the non-oxygen carrying haemoglobin is what makes up the oxygen saturation.

 The body requires a certain oxygen level in the body to function efficiently. In essence, low levels of SpO2 can lead to a condition known as hypoxemia, which can be very serious and fatal if not attended to urgently. In the medical field, SpO2 is taken as a vital sign reading.

How is oxygen saturation measured?

Oximeter or oxygen measuring sensors are used to measure the oxygen saturation level in the blood. 

The clinically used device for this purpose is called a pulse oximeter which is a small electronic device that clips onto the finger. It measures the heart rate and the blood oxygen saturation levels.

Instructions on how to measure oxygen saturation using your Samsung smartphone

Step 1: Tap on the Samsung Health app on your Samsung smartphone

Step 2: Scroll through to the Stress tab and tap Measure

Step 3: You will notice the sensor at the back emitting red light. Place your fingertip on the SpO2 sensor and make sure you stay still while you’re taking the measurement

Step 4: Once completed, lift off your fingertip from the sensor and you can review your data on the resulting My Stress screen

The mechanism behind the Samsung Health SpO2 measurement

The MAX86916 is used in the Samsung s10 which is a separately manufactured biosensor made by Maxim Integrated. It is an integrated optical sensor with applications in bio-sensing, proximity and colour. The internal structure of MAX86916 includes LEDs, photodetectors, and low-noise electronics with ambient-light-rejection circuitry [1].

LEDs are Light-emitting diodes that emit light of a certain wavelength. For the measurement of SpO2, red light is used in conjunction with Infrared Radiation. The LEDs present in the MAX86916 sensor emit light onto the fingertip. 

Photodetectors are light-sensing detectors that detect the amount of light absorbed. Oxygenated blood has characteristic properties that absorb light of a certain wavelength. Oxygenated haemoglobin absorbs more infrared light and allows more red light to pass through. On the contrary, deoxygenated haemoglobin absorbs more red light and allows more infrared light to pass through. 

Photodetectors can sense the amount of infrared light absorbed compared to red light and this ratio can successfully tell how oxygenated the blood is. The photodetector is used to measure light transmission or reflection from a body segment such as a finger at two different wavelengths (usually in the red and infra-red).

A higher infrared red absorption represents more oxygenated blood and a higher red light absorption portrays that the blood is low in oxygen

What is a healthy SpO2 reading?

When measuring the oxygen saturation, a percentage will be displayed on the screen. This percentage should be between 94 percent and 100 percent, this is indicative of a healthy level of haemoglobin carrying oxygen through the blood. If the reading falls below 90 percent, you should see a doctor.

Should I use my phone to check my blood oxygen levels?

Pulse oximeters are designated devices for clinically measuring blood oxygen levels. Today, however, smartphones such as the Samsung Galaxy Smartphones come with an inbuilt oxygen sensor. This makes it easier to measure blood oxygen levels at home. In a pandemic stricken world where COVID-19 has been known to create low levels of oxygen in patients, it would be helpful to know SpO2 concentrations to diagnose any serious health condition. The Samsung Health app has definitely been useful in such scenarios. The question however remains on how accurate the smartphone sensor would be as compared to the clinically used device. It begs to ask if it can be used as a replacement or not?

How accurate is Samsung Health SpO2 measurement?

The Samsung Galaxy SpO2 sensors measure with an accuracy of 90-100%. However, they cannot be replacements to the clinically used device, as the mechanism by which the smartphone measures saturation is slightly different compared to the medically used device.

What are the benefits of knowing your oxygen saturation levels?

During the pandemic, individuals with COVID-19 showed lower oxygen levels because their pulmonary capacity was reduced due to COVID-19 being a respiratory virus. This meant that knowing oxygen saturation levels could be very useful in such cases especially since shortness of breath, a symptom of the disease, may not be easily manifested in this disease for a person to be perceptive. In some cases, doctors have reported that some COVID-19 patients suddenly develop a condition called “silent hypoxia,” where people are visibly comfortable and do not notice any shortness of breath, but their oxygen levels are dangerously low. This can happen to both a patient at home or at the hospital. In cases of such a situation arising in a patient at home, the Samsung Health app would be of great benefit as it would show low SpO2 levels that can be a sign of danger and the test might help to get the patient to respective medical care.


In this brief article, we answered the question of ‘ How Samsung Health measures blood oxygen levels, and provided more tips on the benefits of knowing oxygen saturation levels and the role of smartphones in doing so.