Patent ID: 6640117
Filing Date: 2003-10-28
Classification: A61B

Abstract:
A method for controlling spectral effects attributable to tissue state variations during NIR-based, non-invasive blood analyte determination, comprising the steps of:determining a target range of values for a selected tissue state parameter, said tissue state parameter comprising skin temperature in the vicinity of a tissue measurement site on a body part of a live subject; providing means for modifying said tissue state parameter; providing a calibration model, developed using a calibration data set that includes spectral measurements on a group of exemplary subjects combined with associated skin temperature reference measurements, said calibration developed using multivariate analytical techniques, that correlates said spectral effects to variations in said tissue state parameter, said spectral effects comprising shifts in a peak water absorbance band in an NIP spectrum, wherein said model implicitly incorporates said shift information in multivariate regression coefficients; monitoring said tissue state parameter by measuring an NIR spectrum and calculating values for said parameter from said spectrum according to said calibration model; and if said calculated value is outside of said target range, modifying said tissue state parameter until a measured value for said parameter is within said target range.