Analysis system for determining an analyte concentration, taking into consideration sample-and analyte-independent light-intensity changes
First Claim
1. Analytical system for determining an analyte in which non-analyte-dependent light intensity changes are taken into account comprising a test element which, before sample application, has an absorption of light in a first wavelength range which is previously known and is not equal to zero, an illumination unit which emits radiation in the first wavelength range and in a second wavelength range and irradiates the test element, a detector unit which is positioned in such a manner that light transmitted or reflected by the test element is registered, an evaluation unit which receives signals from the detector when it is irradiated and which is used to determine a correction value from an absorption of the test element in the first wavelength range and is used to determine a measured value in the second wavelength range which is dependent on the analyte concentration after sample application on the test element, and is used to determine the concentration of the analyte taking into account the correction value.
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Abstract
The invention concerns an analytical system and a method for determining an analyte which ensures an exact determination by correcting the measured values based on sample- and analyte-independent light intensity changes. The invention takes into account light intensity changes which are based on changes of measurement conditions in the apparatus. The invention is particularly suitable for use in analytical systems for glucose determination in which light-conducting test elements are used.
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Citations
24 Claims
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1. Analytical system for determining an analyte in which non-analyte-dependent light intensity changes are taken into account comprising
a test element which, before sample application, has an absorption of light in a first wavelength range which is previously known and is not equal to zero, an illumination unit which emits radiation in the first wavelength range and in a second wavelength range and irradiates the test element, a detector unit which is positioned in such a manner that light transmitted or reflected by the test element is registered, an evaluation unit which receives signals from the detector when it is irradiated and which is used to determine a correction value from an absorption of the test element in the first wavelength range and is used to determine a measured value in the second wavelength range which is dependent on the analyte concentration after sample application on the test element, and is used to determine the concentration of the analyte taking into account the correction value.
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8. Method for analysing and correcting non-analyte-dependent changes in light intensity comprising the steps
(a) irradiating a test element before sample application and detecting the light reflected or transmitted by the test element in a first wavelength range in which an absorption by the test element to which the sample has not been added takes place which is previously known and is not equal to zero and determining a first correction value, (b) irradiating the test element after adding the sample and detecting the light reflected or transmitted by the test element in the first wavelength range in which the previously known absorption of the dry test element and an analyte-independent, sample-dependent light intensity change takes place and determining a second correction value, subsequently or before method step (b), irradiating the test element and detecting the light reflected or transmitted by the test element in a second wavelength range in which an absorption by an analyte takes place and determining the measured value computing for the first and second correction value in order to determine the proportion of the light intensity changes that are due to the sample, determining the amount of light (black value) that is registered by the detector when there is an essentially complete absorption of the dry test element using the first correction value, calculating the analyte concentration in the second wavelength range with a correction of the measured value taking into account the black value and the sample-dependent change in light intensity.
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15. Method for analysing and correcting non-analyte-dependent changes in light intensity comprising the steps
irradiating a test element in a first wavelength range before or after sample application where the test element has an absorption in the first wavelength range before sample application which is previously known and is not equal to zero, detecting the light reflected or transmitted by the test element in a first wavelength range and determining a first or a second correction value, irradiating the test element after sample application and detecting the light reflected or transmitted by the test element in a second wavelength range in which an absorption by an analyte takes place and determining the measured value, determining the analyte concentration with a correction of the measured value taking into account the first or second correction value.
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19. Test element having light-conducting properties for applying and analysing samples comprising
a substance which has a sample-independent and previously known absorption in a first wavelength range which is not equal to zero, a reagent system which interacts with an analyte in the sample such that the test element has an analyte-dependent absorption in a second wavelength range after sample application.
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23. (cancelled)
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24. (cancelled)
Specification