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An apparatus and method for testing the glucose level in a blood sample is provided. The method includes the step of initially filtering a sample of blood to be tested. A beam of light is provided and split into a pair of beams by a beam splitter. The pair of beams travel along generally parallel paths. One path contains a cell of a known optical pathlength and additionally a compensator. The other path has a cell containing the filtered blood sample to be tested. The pair of beams are then recombined by a mirror and a fringe pattern is detected at a detector. From the fringe pattern, the refractive index of the blood sample can be calculated. The refractive index is easily converted to a specific glucose concentration. Alternatively, the original fringe pattern can be restored by changing the effect of the compensator. The refractive index can then be found from the required compensation.

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Board of Control of Michigan Technological University, Houghton, Mich.

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Interferometric measurement of glucose by refractive index determination

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