Patent ID: 7751863

Claim:
A method for determining blood pH and glucose concentration with one fluorescent dye, comprising: providing a device comprising: an optical sensor, comprising an indicator system, comprising: a fluorophore that exists in at least first and second different forms depending on the blood pH, wherein the different forms can be distinguished based on their respective first and second emissions; and a binding moiety that binds glucose, wherein the binding moiety is operably coupled to said fluorophore, and wherein binding of glucose by said binding moiety causes an optical change in the apparent concentration of said fluorophore related to a concentration of glucose; wherein a ratio of said first and second emissions is independent of the concentration of glucose; at least one light source; at least one detector configured to detect both said first and second emissions; and a controller configured to monitor signals from said at least one detector and determine said ratio: inserting said sensor into a blood vessel; irradiating said sensor using said at least one light source; detecting the first emission corresponding to the first form of the fluorophore; detecting the second emission corresponding to the second form of the fluorophore; ratiometrically determining the blood pH using said controller; and determining the blood glucose concentration corrected for pH using said controller.