Patent ID: 6130743
Filing Date: 2000-10-10
Classification: G01N

Abstract:
A colorimetric red blood cell sensor, comprising:a tube for conveying blood plasma;a red light source for generating a pulsed red light signal that is directed through said tube;a blue light source for generating a pulsed blue light signal that is directed through said tube, where said pulsed blue light signal is about 180 degrees out of phase with respect to said pulsed red light signal;a photodetector system, positioned such that said tube is interposed between said red and blue light sources and said photodetector system, for detecting the intensities of said red light signal and said blue light signal, and for generating a first output signal alternately representing the intensities of said red and blue light signals detected by said photodetector; anda processor for implementing processor functions in response to receiving said first output signal from said photodetector, where said processor functions include: a) determining the value of the ratio of I.sub.R /I.sub.B, where I.sub.R represents said intensity of said pulsed red light signal detected by said photodetector and I.sup.B represents said intensity of said pulsed blue light signal detected by said photodetector; and b) generating a second output signal when I.sub.R /I.sub.B >.epsilon., where .epsilon. represents a limit.