Noninvasive measurement of glucose through the optical properties of tissue

An apparatus for noninvasive measurement of a target analyte in a tissue sample comprising:

• means for measuring a spectrum of a tissue sample:
• means for detecting at least one optical property of said tissue sample related to fluid shift between extravascular and intravascular tissue compartments triggered by change in concentration of said analyte, as manifested by at least one spectral features reflecting said fluid shifts;
• and
• either correcting a direct analyte measurement on the basis of said at least one optical property;
• or
• measuring said analyte indirectly on the basis of said at least one optical property.

A method for noninvasive measurement of a target analyte property in a tissue sample, comprising the steps of:

• noninvasively measuring a spectrum of a tissue sample in vivo;
• detecting at least one optical property of said tissue sample related to physiologic state of said tissue resulting from change in concentration of said analyte, as manifested by at least one spectral feature reflecting said physiologic state;
• and
• either correcting a direct analyte measurement on the basis of said at least one optical property;
• or
• measuring said analyte indirectly on the basis of said at least one optical property.

A method for noninvasive measurement of glucose concentration in a tissue sample, comprising the steps of:

• measuring a spectrum of a tissue sample;
• detecting at least one optical property of said tissue sample related to state of said tissue resulting from change in concentration of glucose, as manifested by at lest one spectral feature reflecting said state;
• and
• either correcting a direct glucose measurement on the basis of said at least one optical property;
• or
• measuring said glucose concentration indirectly on the basis of said at least one optical property.

A method for noninvasive measurement of a target analyte in a tissue sample, comprising the steps of:

• measuring a spectrum of a tissue sample;
• detecting conditions not conducive to analyte measurement;
• if conditions are conducive to analyte measurement, detecting at least one optical property of said tissue sample related to physiology of said tissue resulting from change in concentration of said analyte, as manifested by at least one spectral feature reflecting said physiology;
• and
• either correcting a direct analyte measurement on the basis of said at least one spectral feature;
• or
• measuring said analyte indirectly on the basis of said at least one optical property.