Patent ID: 7027848

Claim:
A method for performing modifications to calibration models in the non-invasive spectroscopic measurement of an analyte or attribute of tissue, the method comprising the steps of: providing a means for irradiating tissue with infrared energy; providing an output element, the output element operatively connected to a means for measuring a spectrum; irradiating tissue with the infrared energy so that there is absorption of at least a portion of the infrared energy in the tissue; collecting at least a portion of the infrared energy exiting the tissue through the output element and measuring the resulting spectrum; collecting at least one matched reference sample that is assayed to determine at least one reference value of the analyte or attribute of tissue; and using the at least one reference value with the spectral measurement to perform a modification to the calibration model; wherein the matched reference sample is a fluid taken from a tissue compartment that is kinetically matched to the tissue which is irradiated.