Abstract: Concentration of a target chemical in the presence of other substances in a specimen is determined by subjecting the specimen to radio frequency electromagnetic components, sequentially or otherwise, ranging to about 5 GHz. The reflected and/or transmitted signal real and imaginary components at the specimen are spectrally examined as a function of frequency to identify the presence and/or concentration of the chemical of interest. Such examination includes analysis of the effective complex impedance presented by the specimen, and/or effective phase shift between the transmitted and reflected signal at the specimen. The effects upon glucose concentration measurements of varying electrolytes, primarily NaCl, can be nulled-out by examining impedance magnitude at a cross-over frequency, for example about 2.5 GHz. NaCl concentration exhibits a very linear relationship with phase shift change at frequencies in the 2 GHz-3 GHz range.

Abstract: An apparatus and process for accurately determining settling data for the settling of erythrocyte cells from a plasma fluid in a test specimen of blood. The apparatus includes a settling tube, a sensing assembly movably mounted proximate the settling tube. Preferably an infrared emitter and detector are provided in the sensing assembly, and a control assembly is provided which senses data at a high rate and is responsive to the sensed data to sample or store the time at which sensed reflectivity exceeds a threshold level. When the threshold is reached, data is sampled and the tracking head is moved by a very small step. This process is repeated to enable tracking of the descent of the separation boundary between the erythrocyte cells and plasma fluid. The apparatus senses changes in reflectivity of the erythrocyte portion of the specimen below and up to the separation boundary.

Abstract: An apparatus and process for accurately determining settling data for the settling of erythrocyte cells from a plasma fluid in a test specimen of blood. The apparatus includes a settling tube, a sensing assembly movably mounted proximate the settling tube. Preferably an infrared emitter and detector are provided in the sensing assembly, and a control assembly is provided which senses data at a high rate and is responsive to the sensed data to sample or store the time at which sensed reflectivity exceeds a threshold level. When the threshold is reached, data is sampled and the tracking head is moved by a very small step. This process is repeated to enable tracking of the descent of the separation boundary between the erythrocyte cells and plasma fluid. The apparatus senses changes in reflectivity of the erythrocyte portion of the specimen below and up to the separation boundary.

Abstract: An apparatus and method for measuring the permittivity of a polar solution specimen to enable a determination of the concentration of polar constituents in the specimen. The apparatus (10) employs a band pass filter including containment means (18) formed to contain the polar solution (26) therein and electrically dispose the polar solution (26) as a dielectric element in the band pass filter; conducting means (12); a source of electrical current (56) connected to said band pass filter; frequency variation means (52) electrically connected to the electric voltage source (56) to enable variation of the frequency at which current is applied to the band pass filter; and voltage sensing means (52) electrically connected to sense the peak voltage passed by the band pass filter.

Abstract: An apparatus and process for accurately determining settling data for the settling of erythrocyte cells from a plasma fluid in a test specimen of blood. The apparatus includes a settling tube, a sensing assembly movably mounted proximate the settling tube. Preferably an infrared emitter and detector are provided in the sensing assembly, and a control assembly is provided which senses data at a high rate and is responsive to the sensed data to sample or store the time at which sensed reflectivity exceeds a threshold level. When the threshold is reached, data is sampled and the tracking head is moved by a very small step. This process is repeated to enable tracking of the descent of the separation boundary between the erythrocyte cells and plasma fluid. The apparatus senses changes in reflectivity of the erythrocyte portion of the specimen below and up to the separation boundary.

Abstract: An apparatus and method for measuring the concentration of a chemical substance in a test sample based on a technique of waveform distortion analysis is disclosed. The apparatus includes a waveform generator that generates a periodic electromagnetic signal having a plurality of frequencies simultaneously present. Preferably the signal has a fundamental frequency and simultaneously present harmonic frequencies which shape the waveform. The shaped periodic signal is transmitted through the test sample by a probe assembly which also receives the transmitted signal from the test sample. Propagation of the shaped signal through the test sample results in a change in the waveform shape or distortion by the chemical, and a detector circuit is provided that quantifies the change in shape of the signal to determine the concentration of the chemical in the test sample.