Abstract: An automated immunoassay analyzer includes a computer controlled instrument (10) and display (16). The display (16) provides a real-time presentation of all operations being performed within the instrument (10). A large number of samples can be loaded into the instrument (10), and the order of testing the samples can be rearranged according to a priority determined by the operator at any time. A wide variety of immunoassays can be performed on each sample and several different immunoassays can be performed on any one sample. Information related to the type of immunoassays being performed on particular samples is collected by a bar code reader (44) and this information is conveyed to the computer (12) for presentation on the display (16). The computer (12) tracks the progress of each immunoassay through the reaction circuit to the detection station (46).

Abstract: An optical detector circuit for a photometric instrument for providing a high precision, low cost A/D conversion of a detected optical signal. A sampled signal is integrated in a sample signal integrator while a reference signal integrator is integrated in a reference signal integrator. Using dual slope techniques, the integrated reference signal is provided as an input signal to the sample signal integrator during a de-integration cycle to provide a ratio of the detected signal to the reference signal, useful in nephelometers. An inverted blanking signal may also be integrated in the sample integrator prior to an integration of the sample signal to improve the accuracy of the dual slope integration. The period of integration is selected as a multiple of the primary sources of interfering noise such as power line and flourescent light frequencies.

Abstract: A color analyzer simultaneously responsive to light intensity at multiple wavelength regions emitted by or reflected from a specimen illuminated by existing ambient light for instantaneously determining relative ratios of the wavelength regions comprising a plurality of interchangeable photodetectors having different spectral response characteristics; a separate optical probe for each photodetector for imaging the light emitted by or reflected from the specimen onto its associated photodetector, the optical probes having identical dimensions and imaging characteristics and being arranged in side-by-side, parallel relationship in order to permit each optical probe to be affected equally by ambient light changes; and means responsive to the outputs of the photodetectors for rationing such outputs and providing the resultant ratio signals for utilization. Also disclosed is a closed loop feedback system to permit the individual ratios of any or all of the photodetectors to be monitored simultaneously.