Glucose Measurement Using Multi-Pulse Voltage Transients
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Solution Overview
Problem
Existing glucose measurement systems, such as the One-Touch Verio, are susceptible to interference from hematocrit and endogenous reducing agents like uric acid, leading to inaccurate blood glucose readings, especially at high glucose levels, due to inadequate compensation for interfering reducing agents.
Innovation Solution
A modified method for calculating blood glucose concentration using a test strip and test meter system, which applies multiple voltages to measure current transients and employs specific equations to derive an initial glucose proportional current and hematocrit compensation factor, improving accuracy by correcting for interfering substances and hematocrit effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple voltage pulses are applied to measure current transients for glucose detection, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent applies a sequence of periodic voltage pulses (first voltage pulse, second voltage pulse, third voltage pulse) at specific time intervals to the electrochemical cell. Each pulse serves a specific function: the first pulse initiates the reaction, the second pulse measures interference current, and the third pulse measures total current. This periodic application of voltages enables differentiation between glucose signal and interfering substances through temporal separation of measurements.
Solution Approach 2:
The measurement process is segmented into distinct temporal phases corresponding to different voltage applications. The first voltage pulse (0-1 second) separates interference measurement from glucose measurement. The second voltage pulse (1-2 seconds) isolates interference current measurement. The third voltage pulse (2-5 seconds) captures total current including glucose response. This segmentation allows the system to process different measurement objectives in separate time windows.
2Measurement precision
If hematocrit compensation function is applied to correct glucose results, then measurement precision is improved, but reliability deteriorates when interfering reducing agents are present
Solution Approach 1:
The patent extracts the interference current component from the total current measurement by applying a second voltage pulse that selectively measures current from interfering reducing agents (uric acid, ascorbic acid) without glucose contribution. This extracted interference signal (iR) is then subtracted from the total current measurement to obtain a corrected glucose signal, effectively removing the harmful influence of interfering substances before hematocrit compensation is applied.
Solution Approach 2:
The system performs preliminary interference current measurement using the second voltage pulse before conducting the final glucose measurement with the third voltage pulse. By measuring and correcting for interference current in advance, the system prepares a cleaned signal that is then used for accurate hematocrit compensation and glucose calculation, ensuring that compensation functions operate on interference-free data.
3Measurement precision
If interference correction is applied using i2corr function, then measurement precision is improved at medium to high glucose, but reliability worsens at low glucose levels
Solution Approach 1:
The patent implements dynamic measurement protocols that adapt to different glucose concentration ranges. The system uses multiple voltage pulses with different timing and duration parameters optimized for various glucose levels. For low glucose measurements, the system extends measurement time windows and adjusts pulse durations to enhance sensitivity while maintaining interference correction accuracy, making the measurement process flexible rather than fixed.
Solution Approach 2:
The system changes measurement parameters (voltage pulse duration, timing intervals, current integration windows) based on detected glucose concentration levels. When low glucose is detected, the system extends integration times and adjusts voltage pulse characteristics to improve signal-to-noise ratio. This parameter adaptation ensures reliable interference correction across the full glucose measurement range, from hypoglycemic to hyperglycemic conditions.
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
The new method achieves glucose concentration accuracy within ±10 mg/dL bias criteria at various glucose levels, significantly reducing the impact of uric acid interference and hematocrit variations, with over 97% of results meeting stringent reference data criteria.
Implementation Method 1
measuring a current transient output resulting from an electrochemical reaction in a test chamber of the test strip
Data Source
AI summary
Described are methods and systems to apply a plurality of test voltages to the test strip and measure a current transient output resulting from an electrochemical reaction in a test chamber of the test strip so that highly accurate glucose concentration can be determined.