No oximeter? Do not worry! The smartphone app can measure blood oxygen levels with 80% accuracy by shining the phone’s flash through your finger, a study shows
- Blood oxygen levels are currently measured using a pulse oximeter
- However, this makes it difficult to test blood oxygen levels on the go
- Scientists have developed an app that uses the phone’s camera and flash
- It has been shown in tests to detect low blood oxygen levels with an accuracy of 80%
From asthma to Covid-19, various medical conditions may require regular blood oxygen measurements.
Currently, these measurements are taken with a pulse oximeter — a device that attaches to your fingertip or ear — although this can make testing on the go difficult.
Hoping to simplify the process, scientists have developed a smartphone app that uses the device’s camera and flash to measure blood oxygen levels.
During testing, researchers from the University of Washington and the University of California San Diego showed that smartphones can detect blood oxygen saturation levels as low as 70 percent — the lowest level pulse oximeters should be able to measure.
Scientists have developed a smartphone app that uses the device’s camera and flash to measure blood oxygen levels
What is a pulse oximeter?
A pulse oximeter measures how much light is absorbed by your blood.
This tells us how much oxygen your blood contains.
The pulse oximeter shines 2 lights through your fingertip or earlobe: a red light and an infrared light.
Blood that contains a lot of oxygen absorbs more infrared light and transmits more red light.
Blood without enough oxygen absorbs more red light and transmits more infrared light.
When your blood cells don’t have enough oxygen, they appear bluer.
Source: British Lung Foundation
With this system, the user places their finger on the smartphone’s camera and flash before recording a video.
A deep learning algorithm can then use the footage to decipher blood oxygen levels.
To put it to the test, the researchers recruited six participants ranging in age from 20 to 34 years.
Each participant wore a standard pulse oximeter on one finger and then placed another finger on the same hand over a smartphone’s camera and flash.
“The camera records a video: Every time your heart beats, fresh blood flows through the part illuminated by the flash,” said senior author Edward Wang.
“The camera records how much the blood absorbs the light from the flash in each of the three color channels it measures: red, green and blue.
“Then we can feed these intensity measurements into our deep learning model.”
Over the course of 15 minutes, each participant breathed a controlled mixture of oxygen and nitrogen to slowly reduce their oxygen levels.
The results showed that the smartphone correctly predicted whether the test subject had low blood oxygen levels 80 percent of the time.
The researchers hope to continue the research by testing the algorithm on more people.
Each participant wore a standard pulse oximeter on one finger and then placed another finger on the same hand over a smartphone’s camera and flash
Huawei is unveiling a £400 wearable device that can measure your blood pressure by inflating around your wrist
Huawei has launched a smartwatch that inflates around the wrist to take accurate blood pressure readings, just like a cuff around the arm in a doctor’s office.
The Huawei Watch D has an airbag on the inside of the strap that slowly inflates around your wrist.
Blood pressure is a critical indicator of overall health, but when measured by a doctor, it can be altered by what is known as the “white coat effect.” where the blood pressure rises slightly when we are at the doctor’s.
“One of our subjects had thick calluses on their fingers, which made it difficult for our algorithm to accurately determine their blood oxygen levels,” said Jason Hoffman, co-lead author of the study.
“If we expanded this study to include more subjects, we would likely see more people with calluses and more people with different skin tones.
“Then we could potentially have an algorithm with enough complexity to better model all of these differences.”
The researchers emphasize that almost everyone now owns a smartphone.
“That way, you could take multiple measurements with your own device, either for free or at low cost,” said Dr. Matthew Thompson, co-author of the study.
“In an ideal world, this information could be seamlessly transmitted to a doctor’s office.
“This would be very beneficial for telemedicine appointments or for triage nurses to be able to quickly determine if patients need to go to the ER or if they can continue resting at home and schedule an appointment with their GP later.”
The study comes shortly after Huawei launched a smartwatch that inflates around the wrist to take accurate blood pressure readings, just like a cuff around the arm in a doctor’s office.
The new Huawei Watch D has an airbag on the inside of the strap that slowly inflates around your wrist.
Blood pressure is a critical indicator of overall health, but when measured by a doctor, it can be altered by what is known as the “white coat effect.”
Here blood pressure rises slightly when we are at the doctor’s because anxiety increases slightly in a clinical setting.