Patent ID: 8473222

Claim:
A method of estimating glucose concentration in a physiologic fluid comprising: contacting an optical sensor with the physiological fluid, wherein the optical sensor comprises a non-enzymatic, equilibrium fluorescence chemical indicator system disposed along a distal region of an optical fiber, the chemical indicator system comprising a fluorophore operably coupled to a glucose binding moiety, wherein the fluorophore is configured to generate a fluorescent emission signal upon excitation with light, and wherein glucose binding to the glucose binding moiety causes a change in the fluorescent emission signal related to the glucose concentration of the physiological fluid; detecting the fluorescent emission signal indicative of the glucose concentration; contacting a temperature sensing element with the physiological fluid, wherein the temperature sensing element is configured to generate a signal indicative of a temperature of the physiological fluid; detecting the signal indicative of the physiological fluid temperature; contacting a pH sensing element with the physiological fluid, wherein the pH sensing element is configured to generate a signal indicative of a pH of the physiological fluid; detecting the signal indicative of the physiological fluid pH; and transforming the fluorescent emission signal indicative of the glucose concentration utilizing the equation: [ Glu ] = c T , pH * ⌊ G i - a T , pH ⌋ a T , pH + b T , pH - G i , wherein [Glu] is the glucose concentration, G i is the fluorescent emission signal intensity a T,pH is the fluorescent emission signal intensity in the absence of glucose at a particular temperature and pH, b T,pH is the asymptotic signal intensity at infinite glucose concentration, minus the fluorescent signal intensity in the absence of glucose (a T,pH ) at the same particular temperature and pH, and c T,pH is the glucose concentration at which the fluorescent signal intensity is one-half the difference between the asymptotic (b T,pH ) and the background (a T,pH ) at the same particular temperature and pH, wherein a T,pH , b T,pH , and c T,pH are set based on data comprising: temperature and pH calibration data; the detected signal indicative of temperature; and the detected signal indicative of pH.