Glucose Sensor Haematocrit Interference Mitigation
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Solution Overview
Problem
Existing glucose sensor devices face challenges in accurately measuring glucose concentration due to haematocrit interference, with existing methods being complex and requiring adaptations in manufacturing processes, leading to unsatisfactory results.
Innovation Solution
A method involving the application of alternating potentials to determine a reaction parameter indicative of reduced mediator concentration at the counter electrode during specific time periods, which helps in reducing the impact of haematocrit levels on glucose measurement, using a system with multiple electrodes and a water-soluble dry reagent film containing enzymes and mediators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If haematocrit measurement is performed independently and glucose measurement is corrected using the haematocrit measurement, then glucose measurement accuracy is improved, but device complexity and analysis complexity increase
Solution Approach 1:
The patent extracts the haematocrit measurement function from a separate independent measurement and integrates it into the glucose measurement process itself. By using the sensor electrode to simultaneously capture both haematocrit and glucose information through a single measurement sequence, the complexity of separate measurement systems is eliminated while maintaining correction accuracy.
Solution Approach 2:
The patent combines haematocrit measurement and glucose measurement into a unified measurement process. The sensor uses the same electrode and measurement sequence to obtain both haematocrit data (for correction) and glucose data, merging what were previously separate functions into one integrated system that reduces overall device complexity.
2Measurement precision
If multiple voltages are applied over respective durations to correct for haematocrit, then measurement accuracy is improved, but device complexity and manufacturing complexity increase
Solution Approach 1:
The patent employs periodic application of different voltages to the sensor electrode during the measurement sequence. By applying first voltage, then second voltage, then third voltage in periodic succession, the system achieves haematocrit correction and glucose measurement using simple temporal voltage modulation rather than complex hardware modifications, maintaining ease of manufacture.
3Measurement precision
If complex analysis methods are used to estimate haematocrit corrected analyte concentration from multiple test currents, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The patent performs preliminary haematocrit measurement and correction calculations during the initial phases of the measurement sequence, before the final glucose concentration determination. By completing the correction analysis in advance using the first and second voltage measurements, the system simplifies the final glucose calculation while maintaining high accuracy.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach provides a simpler and more accurate method for glucose concentration measurement that is largely independent of haematocrit concentration, reducing errors and improving precision, as demonstrated by calibration curves showing minimal variation across different haematocrit levels.
Implementation Method 1
determining concentration of glucose in a blood sample using a mediated redox reaction
Implementation Method 2
application of a predetermined voltage twice to promote an electrochemical reaction
Data Source
Figure 1A
Figure 1B
Figure 2~4
AI summary
The invention relates to a method of and apparatus for determining concentration of an analyte, such as glucose, in a fluid sample, such as body fluid or control solution, using a mediated redox reaction. In particular, the method relates to mitigation of the effects of haematocrit on the response of sensor device used in such a method or apparatus. The invention describes a method of determining concentration of an analyte in a fluid sample deposited on a sensor device having a working electrode and a counter electrode, in which the electrodes are provided with an enzyme and a mediator for carrying out a mediated redox reaction, the method comprising: applying a first oxidising potential between the working and counter electrodes during a first time period; applying a second reducing potential between the working and counter electrodes during a second time period; determining a reaction parameter, the reaction parameter being indicative of the concentration of reduced mediator at the counter electrode after commencement of the second time period; using the reaction parameter to determine the concentration of analyte.