1. Field of the Invention
The disclosure herein relates generally to determining analyte concentrations within a blood sample.
2. Description of the Related Art
Millions of diabetics are forced to draw blood on a daily basis to determine their blood glucose levels. In addition, the detection of other blood constituents, such as the determination of the concentration of alcohol in the bloodstream, often requires blood withdrawal in order to perform a precise analysis thereof. A search for a noninvasive methodology to accurately determine blood constituent levels has been substantially expanded in order to alleviate the discomfort of these individuals. A significant advance in the state of the art of noninvasive blood constituent analysis has been realized by the development of spectrometers, including xe2x80x9cthermal gradientxe2x80x9d spectrometers, which analyze the absorbance of particular wavelengths of infrared energy passed through and/or emitted by a sample of tissue. These spectroscopic analytical devices typically employ a window or lens for admitting infrared spectra into the device for analysis by infrared detectors.
Although these devices have marked a significant advance in the state of the art of noninvasive blood constituent analysis, further improvements could be made in the performance and ease of manufacture of such devices.
A device and method for determining analyte concentrations within a material sample are provided. A modulating temperature gradient is induced in the sample and resultant, emitted infrared radiation is measured at selected analyte absorbance peaks and reference wavelengths. The modulating temperature gradient is controlled by a surface temperature modulation. A transfer function relating the surface temperature modulation to a modulation of the measured infrared radiation is provided. Phase and magnitude differences in the transfer function are detected. These phase and magnitude differences, having a relationship to analyte concentration, are measured, correlated and processed to determine analyte concentration in the material sample. A method for adjusting an analyte measurement is provided. The method provides a hydration correction process for calibration and correction whereby analyte concentrations within the material sample may be determined. The hydration correction process is particularly suitable for determining blood analyte concentrations within human tissue.
In one embodiment, a method of analyzing a material sample is provided. The material sample is placed in operative engagement with an analyte detection system. The analyte detection system is operated according to an operation algorithm by which said analyte detection system determines an estimated concentration of an analyte in the material sample while reducing the effect of a hydration level of the material sample on said estimated concentration.
In another embodiment, a method of analyzing a material sample is provided. The material sample is placed in operative engagement with an analyte detection system. An estimated concentration of an analyte in the material sample is determined. The effect of a hydration level of the material sample on the estimated concentration is then reduced. Reducing the effect of the hydration level is at least partially comprised of computing a hydration correction coefficient and then computing the estimated concentration based on the hydration correction coefficient.
In one embodiment, an analyte detection system is provided. The analyte detection system comprises a detector array, a processing circuit in communication with the detector array, and a module executable by said processing circuit whereby the processing circuit computes an estimated concentration of an analyte in a material sample and reduces the effect of a hydration level of the material sample on the estimated concentration.