Patent ID: 6869569
Filing Date: 2005-03-22
Classification: G01N,Y10T

Abstract:
1. Apparatus for differentiating a sub-population of blood cells from other blood cells and particles in a blood sample, said apparatus comprising: (a) an optical flow cell through which the individual blood cells and particles of a blood sample can be made to pass, one at a time; (b) a light source for directing a beam of radiation along an optical axis to irradiate individual blood cells and particles passing through said the optical flow cell; (c) a first optical detector positioned at a location to detect back-scattered radiation from an irradiated particle passing through said optical flow cell and for producing a first electrical signal proportional to the level of back-scattered radiation detected, said first optical detector comprising: (i) a photodetector; (ii) a plurality of optical fibers, each fiber having a light-collection end, an opposing light-discharge end, and an intervening light-transport region for transmitting, by multiple internal reflections, light collected by said light-collecting end to said light-discharge end, said light-discharge end being positioned proximate a light-sensitive face of said photodetector; and (iii) a fiber optic holder for positioning the respective light-collecting ends of said optical fibers at a location to collect said back-scattered radiation from an irradiated blood cell or particle; (d) a second optical detector positioned at a location to detect a loss of light in said light beam caused by the presence of a blood cell or particle in said light beam and for producing a second electrical signal proportional to the detected level of said light loss, said second optical detector comprising a light-diffusing element positioned on said optical axis to diffuse said light beam after irradiating said blood cells and particles passing through said optical flow cell, whereby any beam reflections occurring after blood cell or particle irradiation that would otherwise interfere with the detection of back-scattered radiation is minimized; and (e) a logic and control unit for receiving said first and second electrical signals and for differentiating said sub-population of blood cells from said other blood cells and particles based on the first and second electrical signals received.