Can I use my mobile phone apps to monitor my oxygen levels, rather than a pulse oximeter? The consensus seems to be, generally no.
Doctors say one of the best ways to monitor patients with COVID-19 is by tracking their blood oxygen levels, which can show when they have dangerous breathing problems — even if they don’t feel short of breath.
However, research shows pulse oximetry apps don’t accurately measure blood oxygen levels, especially when they’re low.
Apps don’t work well because most use a different mechanism to test blood oxygen levels than standard, medical pulse oximetry devices.
The standard devices send two different wavelengths of light — usually red and infrared — through a fingertip, where there’s lots of blood close to the surface of the skin.
Haemoglobin, the protein that carries oxygen in the blood, absorbs more infrared light when it’s carrying oxygen and more red light when it’s not. The device calculates the difference to determine how much oxygen is circulating.
However, mobile phones, even Samsung ones using red light, can only look for reflected light, which causes problems with measurement.
To monitor for serious health issues, only use CE marked devices.