Non-invasive automatic glucose sensor system
Ocular testing method and apparatus
Method for determining bilirubin concentration from skin reflectance
Transcutaneous pH measuring instrument
ApplicationNo. 527514 filed on 05/23/1990
US Classes:250/345, Plural beam/detector pairs250/339.09, With calibration steps in measurement process250/339.12, Using sample absorption for chemical composition analysis250/343, With means to transmission-test contained fluent material356/39, BLOOD ANALYSIS600/310, Infrared, visible light, or ultraviolet radiation directed on or through body or constituent released therefrom600/316Glucose
ExaminersPrimary: Fields, Carolyn E.
Assistant: Beyer, James
Attorney, Agent or Firm
Foreign Patent References
International ClassG01J 001/16
Foreign Application Priority Data1990-05-23 EP
AbstractA method and apparatus for non-invasively testing analytical substances in turbid matrices i.e. body fluids and tissues. In this method a sample is irradiated with a beam of electromagnetic energy at two alternating wavelenths, λ1 and λ2, at which the absorption by the background is the same but at one of which the radiation is absorbed by the analyte and at the other it is not. The apparatus comprises means which enable to control the input energy at λ1 and λ2 so that at the output from the sample the electric signals issuing after detection cancel in the absence of the analyte in the sample. When analyte is present cancellation no longer occurs and a signal proportional to the analyte concentration in the sample is produced. The apparatus is also designed for shifting the response back to zero when a calibrating known concentration of analyte is used as standard, thus providing a controllable zeroing base line.