US 6,241,663 B1 · Method for improving non-invasive determination of the concentration of analytes in a biological sample

Abstract

A method for determining the concentration of an analyte in a biological sample comprising the steps of: (1) providing an optical measuring instrument that comprises at least one thermally controllable optical measuring element that comes into contact with the surface of the biological sample; (2) applying an inert, thermally conductive, optically transparent coupling agent to the at least one optical measuring element or to the surface of the biological sample or both so that the coupling agent will be disposed at the interface of the surface of the biological sample and the at least one optical measuring element; (3) measuring optical properties of the biological sample by means of the optical measuring instrument; and (4) correlating the optical properties of the biological sample with the concentration of the analyte in the biological sample. A coupling agent suitable for this invention must have several properties to enable it to help decrease measurement variation, especially drift. One of the most important properties is sufficiently high optical stability that the optical properties of the coupling agent do not change even during prolonged experiments, such as oral glucose tolerance tests. Secondly, the coupling agent should have sufficiently high thermal conductivity to allow fast, efficient heat transfer between the optical probe and the biological sample. Third, the coupling agent should have sufficiently high viscosity to prevent it from migrating from the measurement area. Yet, it should also have sufficiently low viscosity to allow sufficient contact between the optical probe and the biological sample and to permeate into any small pockets between the probe and the biological sample that would otherwise be filled with the air. Fourth, the coupling agent should be inert. Material from the coupling agent should not diffuse into the biological sample and material from the biological sample should not diffuse into the coupling agent.

Claims22

Dependent claims

A method for determining the concentration of analyte in a biological sample comprising the steps of:

(1) providing an optical measuring instrument that comprises at least one thermally controllable optical measuring element that comes into contact with a surface of said biological sample;
(2) applying an inert, thermally conductive, optically transparent coupling agent to said at least one optical measuring element or to said surface of said biological sample or both so that said coupling agent will be disposed at the interface of said surface of said biological sample and said at least one optical measuring element, said coupling agent having sufficiently high optical stability that the optical properties of said coupling agent do not change during optical measurements or during storage, said coupling agent having sufficiently high thermal conductivity to allow rapid, efficient heat transfer between said optical measuring element and said biological sample, said coupling agent having sufficiently high viscosity to prevent it from migrating from said interface, said coupling agent having sufficiently low viscosity to allow sufficient contact between said optical measuring element and said biological sample, said coupling agent having a refractive index higher than that of said biological sample over the temperature range of a measurement;
(3) measuring at least one optical property of said biological sample by means of said at least one optical measuring element;
and
(4) correlating the at least one optical property of said biological sample with the concentration of said analyte in said biological sample.

2 more elements

A method for measuring the concentration of an analyte in a tissue of a body part comprising the steps of:

(1) providing an optical measuring instrument that comprises at least one thermally controllable optical measuring element that comes into contact with the surface of said tissue;
(2) applying an inert, thermally conductive, optically transparent coupling agent to said at least one optical measuring element or to the surface of said tissue or both so that said coupling agent will be disposed at the interface of said surface of said tissue and said at least one optical measuring element, said coupling agent having sufficiently high optical stability that the optical properties of said coupling agent do not change during optical measurements or during storage, said coupling agent having sufficiently high thermal conductivity to allow rapid, efficient heat transfer between said optical measuring element and said tissue, said coupling agent having sufficiently high viscosity to prevent it from migrating from said interface, said coupling agent having sufficiently low viscosity to allow sufficient contact between said optical measuring element and said tissue, said coupling agent having a refractive index higher than that of said tissue over the temperature range of a measurement;
(3) inducing a change in the concentration of said analyte in said tissue over a defined period of time;
(4) measuring the change in at least one optical property of said tissue by means of said at least one optical measuring element during said defined period of time;
(5) determining the change in the concentration of said analyte in said tissue by means of a reference method that involves taking a sample from said tissue for analysis during said defined period of time;
(6) correlating the change in said at least one optical property of said tissue with the change in the concentration of the analyte in said tissue to derive calibration data;
and
(7) using said calibration data to determine the concentration of said analyte in said tissue.

5 more elements

Dependencies are inferred from the claim text.

Method for improving non-invasive determination of the concentration of analytes in a biological sample

Life of this patent

Method for improving non-invasive determination of the concentration of analytes in a biological sample

Life of this patent

Abstract

Claims22