The portable noninvasive device operates via a ring-shaped sensor that is fitted on the donor’s finger. The device applies pressure, temporarily gently squeezing the finger to over-systolic pressure, similar to blood pressure measurements, thus occluding local blood flow. During the occlusion, optical elements in the sensor, using an array of calibrated light sources, measure absorption, and scattering of the light transmitted through the finger.
When you or your family or your friends face an emergency situation for blood transfusion due to accidents or surgery, here is a website which will be usefull to find out voluntary blood donors from your locality.Please join in this website and help others in their need.
The website is: http://www.friendstosupport.org