Kromoscopic Identification of in Vivo Water Variations

Abstract

Optical assays for trace analytes in vivo are severely hampered by the predominant optical effects of water throughout the infrared spectrum. These effects must be properly understood and accounted for in order to avoid the occurrence of spurious correlations in data purporting to track concentrations of trace analytes such as glucose. Kromoscopic analysis™, invented for non-invasive optical assay of trace analytes in vivo, uses real time correlations between measurements that are both spatially and temporally congruent and made with multiple detection channels having overlapping spectral sensitivities. In previous work, we have shown how the predominant optical changes due to water movement in vivo can be tracked and accounted for. More in-depth analysis of Kromoscopic data presented here will demonstrate that at least two distinct and uncorrelated modes of optical variation induced by water changes are present during in vivo sampling. Both of these modes of variation must be accounted for to properly minimise their effects on measurements of glucose or other trace analytes in vivo. This minimisation is demonstrated clearly via Kromoscopic analysis, and the resulting requirements of a successful trace analyte measurement are discussed.