3 ms·

https://www.cebm.net/covid-19/question-should-smartphone-apps-be-used-as-oximeters-answer-no/ https://www.cebm.net/covid-19/question-should-smartphone-app... >

by sampo 6y ago

https://www.cebm.net/covid-19/question-should-smartphone-apps-be-used-as-oximeters-answer-no/ https://www.cebm.net/covid-19/question-should-smartphone-app... > It therefore requires the measurement of light transmission or reflection from a body segment such as a finger at two different wavelengths (usually in the red and infra-red). > The Samsung Galaxy series of phones had a red light emitting diode (LED) built into the phone in addition to the flash light and camera. There were no details released by the company of how its app used the LED to estimate oxygen saturation, but it appears from publicity material on YouTube that it worked via a single-wavelength measurement (albeit with a monochromatic light source, the LED) and therefore that oxygen saturation could not be accurately derived from it.

Noumenon72 6y ago
> For the few patients whose oxygen saturation measurements were between 85% and 93%, the difference between the smartphone estimate and the ABG device varied between -5.5% and +2.5%. In other words, the readings become less accurate as the patient becomes more hypoxic. That's accurate enough to tell whether you have serious Covid in many cases, especially if your baseline reading is 99% like mine. "No evidence" has killed a lot of people in this pandemic by discouraging practices that work but haven't been RCT'd. "Should not be trusted" because something has error bars, even when they're smaller than the dangerous range, could kill even more. It's good to have the information out there that this is an inferior way to check, but I already assumed that was true just because it was only a phone app. "Possibly-inaccurate and free" is the choice I want to make with my health. I have low risk and it leaves more oximeters for others.

3 ms·

https://www.cebm.net/covid-19/question-should-smartphone-apps-be-used-as-oximeters-answer-no/ https://www.cebm.net/covid-19/question-should-smartphone-app... >

by sampo 6y ago

Noumenon72 6y ago
> For the few patients whose oxygen saturation measurements were between 85% and 93%, the difference between the smartphone estimate and the ABG device varied between -5.5% and +2.5%. In other words, the readings become less accurate as the patient becomes more hypoxic. That's accurate enough to tell whether you have serious Covid in many cases, especially if your baseline reading is 99% like mine. "No evidence" has killed a lot of people in this pandemic by discouraging practices that work but haven't been RCT'd. "Should not be trusted" because something has error bars, even when they're smaller than the dangerous range, could kill even more. It's good to have the information out there that this is an inferior way to check, but I already assumed that was true just because it was only a phone app. "Possibly-inaccurate and free" is the choice I want to make with my health. I have low risk and it leaves more oximeters for others.