Abstract: A method of detecting at least one analyte in extra-cellular spaces includes the step of inserting a microprobe through the stratum corneum toward the stratum basale of the skin of a subject into extra-cellular spaces containing interstitial fluid having at least one analyte to be detected, said microprobe having a diameter at its tip no larger than approximately 10-50 microns. The method further includes optically testing for a predetermined analyte in the extra-cellular space adjacent the distal end of the microprobe without drawing a sample of the interstitial fluid. Preferably the microprobe body includes a sensor layer covering the distal optical tip of the microprobe body, the sensor layer being adapted to interact with a predetermined analyte to be detected in the interstitial fluid, and an optical detector responsive to interaction of the sensor layer with the predetermined analyte to signal detection of said predetermined analyte.

Abstract: A sensor device for measuring a concentration of a substance within a sample comprises a sensor comprising an optical fiber portion having a first end and a second end, the second end having a tip portion attached thereto and an active material incorporated within the tip portion, the tip portion adapted to be inserted into a sample, the active material capable of interacting with a substance within a sample, a light source coupled to the first end of the sensor for emitting a beam of light into and through the sensor and into a sample, the emitted beam of light having a wavelength and the active material interacting with a substance within a sample to change the wavelength of the emitted beam of light to produce a reflected beam of light and the sensor for transmitting the reflected beam of light out of the second end thereof, an optical detector for receiving the reflected beam of light from the second end of the sensor for producing a signal indicative of the reflected beam of light, and a processor for re