A Multichannel Centrifugal Analyzer. Simultaneous Determination of Multiple Constituents in Clinical Samples

494 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1980.The concept of a multichannel, multiwavelength centrifugal analyzer was investigated because of the potential advantages compared to present instruments. The possibility of rapid, simultaneous, multiple determinations of clinical sample constituents could be especially useful in intensive care units, therapeutic monitoring units, emergency rooms or even admission points to the hospital for admissions screening. The instrument designed and built to test the concept contains six channels, five absorbance and one fluorescence which could provide enough wavelengths to allow twenty of the common clinical chemistry tests to be run on each sample. Stat or routine profiles can be run on the analyzer within 15 minutes of receipt of the sample, with setup, analysis and printout of results requiring less than five minutes. Additionally, single chemistry tests can be run on multiple samples in a batch mode operation to handle those samples requiring only one or a few tests per sample. This flexibility allows the analyzer to be used efficiently to analyze all types of samples received by the laboratory, Stat or routine, single or multitest. Commercially available analyzers are not effective in handling all types of samples.The Multichannel Centrifugal Analyzer is microprocessor controlled. The ease of interfacing the instrument and processor allows a high level of automation to be accomplished with minimal design overhead. To allow all cuvettes to read in each rotation for the desired wavelength, two identical data collection channels are employed with analog and digital multiplexing to select and measure the desired optical channel. To handle the data collection rapidly within the allowed time vectored interrupts and assembly language service programs are utilized. Further programming would allow real-time checking and processing of data. To reduce data processing time, an arithmatic logic unit is used to calculate absorbance values and the sums necessary for obtaining linear least squares regression parameters. BASIC is used for final printing of data. To evaluate the effectiveness of the analyzer in performing both batch analyses and profiles, five chemical methodologies were developed and tested. These were for glucose, creatinine, calcium, total protein and albumin. The method for glucose was a rate method based upon glucose oxidase/peroxidase reactions coupled to a 4-aminoantipyrine and phenol chromophore absorbing at 510 nm. The Jaffe reaction was employed as a rate method for the determination of creatinine and the absorbances were also measured at 510 nm. Total protein was measured by a reaction rate method at 580 nm using a modified biuret reagent. Orthocresolphthlein complexone and bromocresol green equilibrium methods were employed to measure calcium and albumin, respectively, at 580 nm. For the batch mode analyses, working curve standards and quality control sera were run on each disc. Correlation coefficients of 0.9996 were typical for the working curves, with relative standard deviations of 2-5% for most standards. The quality control sera results were well within the assigned or consensus region for each constituent, using both normal and abnormal control sera. Quality control sera was then run as a profile. No significant differences in the results for either profile or batch mode determinations were observable. These tests indicate that the multichannel, multiwavelength centrifugal analyzer could become an important type of instrument in clinical chemistry.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD