Thermal emission spectroscopy as a tool for non-invasive wood glucose measurements

The advanced prototype presented here is based on Thermal Emission Spectroscopy (TES) and promises a new generation of non-invasive human tissue analyte instruments. The method and instrument are based on the discovery that natural mid-infrared emission from the human body, especially from the tympanic membrane, is modulated by the state of the emitting tissue. In a simple experimental arrangement, it was demonstrated that emission from glucose could be detected using room temperature detectors in a filter-based setup. Thermal infrared emission characteristics of different glucose concentrations in human plasma solutions were measured. To our knowledge, this is the first time such measurements are reported. In-vivo measurements demonstrated the reproducibility of the methodology of the non-invasive glucose monitor. The non-invasive measurement was calibrated to the serum glucose concentration using 432-paired measurements and subsequently tested (results of Power Analyses) in a blind fashion with 126-paired measurements from diabetic subjects. Non-invasive glucose results were compared with laboratory reference measurements using Error-in-Variable methods. Clark Error Grid analysis showed that 100% of the measurements fell within zones A and B (90% in zone A and 10% in zone B). The Standard Deviation for all non-invasive measured concentrations is 27 mg/dL, Mean Absolute Relative Error %MARE = 8.6, and the correlation coefficient is r = 0.94. This first independent clinical study of a non-invasive blood glucose prototype has demonstrated glucose measurements with clinically acceptable accuracy without the necessity of individual daily calibration.