Electrochemical Sensor Signal Discrimination via Temporal Verification

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Solution Overview

Problem

Electrochemical measurement devices face challenges in distinguishing between current signals caused by extraneous events, such as electrostatic discharge, and those indicative of measurement errors, leading to false triggers and unnecessary disposal of test strips.

Innovation Solution

The solution involves characterizing current signals based on their timing and duration to differentiate between extraneous events and actual measurement errors, using techniques like ESD check modes and non-parametric filtering to accurately determine the presence of a physiological fluid sample.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a current threshold check is used to detect sample presence, then measurement accuracy is improved, but false error conditions increase due to extraneous signals

Engineering Contradiction:
Improvesample presence detection accuracyVSAvoiderror condition reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The system dynamically adjusts the detection criteria by transitioning from a simple current threshold check to a time-duration-based verification. The measurement cycle is conditionally initiated based on whether the current exceeds the threshold for a predetermined time period, allowing the system to adapt its response based on the temporal characteristics of the signal rather than relying on a static threshold alone.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system performs a preliminary time-duration check before initiating the measurement cycle. By verifying that the current exceeds the threshold for a predetermined time period before triggering measurement, the system preemptively filters out short-duration extraneous signals like electrostatic discharge, preventing false error conditions before they occur.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If a predetermined current threshold is applied to detect sample presence, then false error conditions increase, but measurement precision improves

Engineering Contradiction:
Improveanalyte concentration measurement accuracyVSAvoidextraneous signal interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The system transforms the static current threshold detection into a dynamic time-duration-based detection. Instead of simply checking if current exceeds a threshold, the system verifies that the current remains above the threshold for a predetermined time period, dynamically adjusting the detection criterion to account for signal persistence and thereby distinguishing true sample presence from transient extraneous signals.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system converts the potentially harmful effect of extraneous signals into a beneficial filtering mechanism. By utilizing the short duration characteristic of extraneous signals like electrostatic discharge, the system employs time-duration verification to automatically reject these harmful signals while accepting genuine sample presence indicators, effectively turning the signal's temporal characteristic into a useful discrimination tool.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Object-affected harmful factors

If hardware filters are used to block current spikes, then extraneous signal suppression improves, but device complexity increases

Engineering Contradiction:
Improveelectrostatic discharge suppressionVSAvoidhardware filter configuration
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The system replaces complex hardware filtering mechanisms with a software-based temporal verification approach. Instead of using physical filters to block current spikes, the system uses firmware logic to detect and ignore signals that do not persist for the predetermined time period, substituting mechanical/electrical filtering with a software-based temporal discrimination method that reduces hardware complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system employs self-service signal verification by using its own measurement timing and current monitoring capabilities to automatically distinguish valid signals from extraneous ones. The predetermined time period requirement enables the system to self-verify signal validity without requiring external filtering hardware, allowing the measurement system to service its own signal validation needs.

Inventive Principle:
Principle #25Self-service

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 effectively reduces false error conditions by correctly identifying and ignoring extraneous signals, ensuring accurate glucose concentration measurements and preventing unnecessary test strip disposal.

Implementation Method 1

The fluid chemically reacts with the reagent in a way that changes a measurable electrical property of the reaction fluid (its conductivity, for example) that can be correlated to a concentration of the analyte of interest

Methodology Applied
Scientific EffectElectrochemical reaction: Redox Reactions

Implementation Method 2

an electrical characteristic of the reaction fluid (typically its ability to conduct a current) can be measured with a suitable electronic system

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

Electrostatic discharge can, under certain circumstances, provide a false signal. Electrostatic discharge typically provides a short duration current with high voltage within an electrode that may be detected

Methodology Applied
Scientific EffectElectrostatic discharge: Electrostatic Discharge

Data Source

PatentEP2261651B1Method and apparatus for measuring physiological fluids
Publication Date: 2016.04.20 LIFESCAN INC
  • EP2261651B1 patent drawingFigure 1
  • EP2261651B1 patent drawingFigure 2
  • EP2261651B1 patent drawingFigure 3~4

AI summary

Electrochemical measurement techniques for measuring the concentration of an analyte in a physiological fluid sample are described. More particularly, the present invention relates to techniques for distinguishing a signal caused by an extraneous event from a desired information providing signal such as one indicative of a measurement error.