Oxygenated blood absorbs infrared light proportionally to the amount of oxygen carried by red blood cells. On the contrary red light is absorbed most by not oxygenated blood, or at an inverse proportion of the presence of oxygen on red blood cells. By calculating the ratio of infrared vs red light absorption an oximeter placed on your finger tip can calculate the oxygenation percentage, a crucial parameters to evaluate how your lungs and heart are doing their job.
The oximeter has become a standard equipment in ER, easy to use and fast in providing a first indication of the status of the patient. The cost is in the range of 50 to 500$ depending on the kind of performance and accuracy. It is not particularly expensive but it is not cheap either, not something you want to dispose once used. And indeed in ER oximeters are disinfected and used over and over.
Now researchers at Berkeley have created a very low cost disposable oximeter based on organic LED and plastic light detectors, as shown in the figure.
You can read more following the link.
It is not a game changer, since today's oximeters are already affordable, but I decided to report the news because it shows an interesting use of organic electronics. By being so cheap, one can easily imagine that a variety of sensors will be developed and will become part of the "standard" equipment in our life, as it happened to the thermometer.