Method and apparatus for minimizing spectral effects attributable to tissue state variations during NIR-based non-invasive blood analyte determination

An apparatus for controlling spectral effects attributable to tissue state variations during NIR-based, non-invasive blood analyte determination, comprising:

• means for modifying a selected tissue state parameter, wherein said tissue state parameter comprises skin temperature in the vicinity of a tissue measurement site on a body part of a live subject;
• means for measuring an NIR spectrum at a tissue measurement site;
• a calibration model that correlates said spectral effects to variations in said tissue state parameter, wherein said calibration model is developed using a calibration data set that includes spectral measurements or a group of exemplary subjects combined with associated skin temperature reference measurements, said spectral effects comprising shifts in a peak water absorbance band in an NIR spectrum;
• means for monitoring said tissue state parameter by measuring an NIR spectrum and calculating values for said parameter from said spectrum according to said calibration model;
• wherein said tissue state parameter is modified by said modifying means if said calculated value is outside of a target range until said parameter is within said target range.

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 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 NIR spectrum, said target range comprising a range of skin temperatures wherein said shifts are minimized;
• 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.