Patent ID: 7277740
Filing Date: 2007-10-02
Classification: A61B,G01N,G02B

Abstract:
1. A system for the reagent-free determination of the concentration of an analyte in living tissue of a patient, the system comprising: a light transmitter for generating monochromatic primary light having a wavelength of at least 550 nm and at most 900 nm; a scattered-light percutaneous sensor adapted to be inserted through the skin surface into the skin, wherein a distal end of the percutaneous sensor has a sensor head, wherein a distal end of the sensor head is enclosed by a semipermeable membrane to define a test volume for containing interstitial fluid from the tissue, wherein the semipermeable membrane prevents admission of macromolecules having a molecular weight above the exclusion limit of the semipermeable membrane to the test volume; an inbound light guide in which the primary light is conducted through the skin surface into the interior of the body; a light irradiation surface formed at a distal end of the inbound light guide through which the primary light penetrates into the test volume; a detection light guide which has at its distal end a light receiving surface through which a secondary light scattered in the test volume penetrates into the detection light guide, wherein the light irradiation surface of the inbound light guide and the light receiving surface of the detection light guide are adapted to be located subcutaneously so that the test volume contains the interstitial fluid; a wavelength-sensitive detection device connected to the detection light guide for detection of Raman-scattered components of the secondary light; and an evaluation device for determining the concentration of the analyte from the Raman-scattered components of the secondary light.