Image Number 7 for United States Patent #5431880.
A light transmittance type analytical system for the rapid quantitation of minute amounts of an analyte in a fluid sample and an optical component and test device useful therein are; disclosed. The analytical system employs an assay in which the presence of the analyte in the assayed sample is productive of an insoluble substantially opaque, light absorptive colored end product. In the preferred use of the analytical system, the end product is formed in contact with a light and fluid permeable optical component in the form of a matrix of compacted substantially water insoluble granules of reflective material which has a light scattering coefficient of at least about 80 and is substantially nonabsorptive of light. Contact of particles of the end product with granules of the matrix causes a rapid and dramatic reduction in the light transmittance capability of the matrix which is monitored by the instrument to provide amplified quantitation of the analyte, which quantitation results from the two-fold effect of direct absorption of light by the end product, and reduction of the light scattering coefficient of the matrix granules caused by contact thereof by the end product. The instrument performs all of the steps of the assay when the test device is in operative position therein, and is well adapted for preprogrammed automated operation under computer control.