Optics: measuring and testing – By particle light scattering – With photocell detection
Patent
1995-10-10
1998-01-20
Turner, Samuel A.
Optics: measuring and testing
By particle light scattering
With photocell detection
356346, 356 39, 25022727, 128633, G01B 902
Patent
active
057106304
DESCRIPTION:
BRIEF SUMMARY
The invention concerns a method for the analysis of glucose in a biological sample and a related glucose measuring apparatus.
The term "biological sample" denotes a body fluid or tissue of a living organism. Biological samples are generally optically heterogeneous, that is, they contain a plurality of scattering centers scattering irradiated light. In the case of biological tissue, especially skin tissue, the cell walls and other intra-tissue components form the scattering centers.
Body fluids, in particular blood, also constitute optically heterogeneous samples because containing particles which scatter the irradiated light. Milk and other foodstuff-chemistry liquids also frequently contain high concentrations of scattering centers, for instance in the form of emulsified droplets of fat.
The invention is suitable for the analysis in comparatively highly scattering, i.e. optically heterogeneous biological samples. However optically homogeneous (that is, low-scattering or entirely non-scattering) samples also may be analyzed by the invention provided suitable embodiments of the invention be employed.
Generally for the qualitative and quantitative analysis in such biological samples reagents or systems of reagents are used that chemically react with the particular component(s) to be determined. The reaction results in a physically detectable change in the solution of reaction, for instance a change in its color, which can be measured as a measurement quantity. By calibrating with standard samples of known concentration, a correlation is determined between the values of the measurement quantity measured at different concentrations and the particular concentration. These procedures allow highly accurate and sensitive analyses, but on the other hand they require removing a liquid sample, especially a blood sample, from the body for the analysis ("invasive analysis"). This blood sampling is unpleasant and painful and includes some risk of infection.
This is foremost the case where a disease requires very frequent analysis. The most important example is diabetes mellitus. To avert serious consequential illness and critical patient conditions, this disease requires determining the blood glucose content very frequently or even continually.
Accordingly a number of procedures and apparatus have been suggested to determine glucose in blood, tissue and other biological samples in vivo and in a non-invasive manner.
A survey of physico-chemical (reagent-free) in-vivo glucose determinations is found in J. D. Kruse-Jarres, J. Clin. Chem. Clin. Biochem. 26 (1988), pp 201-208. Non-invasive procedures described therein include nuclear magnetic resonance (NMR), electron spin resonance (ESR) and infrared spectroscopy. However none of these procedures has achieved practical significance. Large and costly equipment is required, which are wholly unsuitable for routine analysis or even for patient self-checking (home monitoring).
The invention concerns a sub-set of such procedures wherein measuring light from a light source is irradiated as primary light through a boundary surface bounding the sample and wherein light exiting the biological sample through this boundary layer is detected by a photodetector in order to determine a physical light property which is affected by the interaction of light with the biological sample (without using reagents), said propertly correlating with the glucose concentration in the biological sample. Such a method step is termed hereafter as a "detection step".
The physical light property correlating with the glucose concentration and determined in a detection step (which also may be designated as a quantifiable parameter) is termed hereafter for the sake of simplicity "measurement quantity". However this term should not be understood to require that a particular magnitude of the measurement quantity must be measured in a corresponding dimensional unit.
The methods discussed herein generally do not allow an absolute measurement of the glucose concentration, and therefore (as in the conventional analy
REFERENCES:
patent: 4632554 (1986-12-01), Pearce
patent: 4883953 (1989-11-01), Koashi et al.
patent: 5028787 (1991-07-01), Rosenthal et al.
patent: 5146091 (1992-09-01), Knudson
Kruse-Jarres, J.Clin. Chem. Clin. Biochem., "Physicochemical Determinationas of Glucose in vivo", vol. 26, 1988, pp. 201-208.
International Publication No., WO 93/00856 published Jan. 21, 1993.
Danielson et al., Applied Optics, "Guided-wave reflectometry with micrometer resolution", vol. 26, No. 14, 15 Jul. 1987.
Takada et al., Applied Optics, "New measurement system for fault location in optical waveguide devices based on an interferometric technique", vol. 26, No. 9, 1 May 1987.
Schmitt et al., Applied optics, "Measurement of optical properties of biological tissues by low-coherence reflectometry", vol. 32, No. 30, 20 Oct. 1993.
International Publication No. WO 92/19930 published Nov. 12, 1992.
Huang et al., Science, "Optical Coherence Tomography", vol. 254.
Boecker Dirk
Essenpreis Matthias
Knuettel Alexander
Boehringer Mannheim GmbH
Turner Samuel A.
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