CMOS Detector Array for Hematocrit and Volume Correction

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Solution Overview

Problem

Conventional glucose monitoring technologies face inaccuracies due to variations in hematocrit levels and sample volume, leading to errors in glucose concentration measurements, and lack the ability to detect and correct for non-ideal reaction spots, which are common in photometric methods used for diabetes management.

Innovation Solution

The implementation of a CMOS-based detector array that corrects for hematocrit levels and sample volume variations, provides feedback for automated sampling, and compensates for imperfections in reaction spots, using algorithms to calculate analyte concentration accurately across a broader range of hematocrit levels and sample volumes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional photometric methods are used for glucose monitoring, then the measurement process is simple and quick, but the accuracy of glucose concentration measurements deteriorates due to variations in hematocrit levels and sample volume

Engineering Contradiction:
Improveaccuracy of glucose concentration measurementVSAvoidcomplexity of detector system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The detector is divided into multiple detector elements arranged in an array, where each element independently measures light properties at different positions. This segmentation allows the system to capture spatial variations in the reaction spot, enabling hematocrit and volume corrections without requiring a single complex detector.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a single-point measurement to a two-dimensional array of detector elements. By measuring light properties across multiple positions simultaneously, the system adds spatial dimensionality to the measurement, enabling it to detect and correct for variations in hematocrit and sample volume based on the distribution of reaction intensity across the array.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If the detector array is used to correct for hematocrit and volume variations, then measurement accuracy improves, but the device complexity increases

Engineering Contradiction:
Improvereliability of glucose monitoringVSAvoidcomplexity of detector array system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The detector array serves multiple functions: it measures the primary analyte concentration, detects hematocrit variations, determines sample volume, and identifies non-ideal reaction spots. This multi-functionality allows a single device component to address multiple sources of measurement error, improving reliability without proportionally increasing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses the measurements from the detector array to generate feedback about hematocrit levels, sample volume, and reaction spot quality. This feedback is then used to correct the glucose concentration measurement in real-time, creating a closed-loop system that automatically compensates for variations and improves reliability.

Inventive Principle:
Principle #23Feedback

3Ease of operation

If a fixed calibration is used for the meter, then the device is simple to operate, but the accuracy deteriorates when sample volume varies from the calibrated amount

Engineering Contradiction:
Improvesimplicity of meter operationVSAvoidaccuracy of glucose measurement
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The system automatically determines the actual sample volume applied to the test strip using the detector array measurements, and self-corrects the glucose concentration reading based on this detected volume. This eliminates the need for users to manually measure or control sample volume, maintaining ease of operation while improving accuracy through automatic volume compensation.

Inventive Principle:
Principle #25Self-service

4Adaptability or versatility

If conventional detectors are used, then the device structure is simple, but the ability to detect and correct for non-ideal reaction spots is lost

Engineering Contradiction:
Improveability to handle non-ideal reaction spotsVSAvoiddetector configuration
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The detector is segmented into multiple elements that can independently evaluate different regions of the reaction spot. This allows the system to identify non-ideal spots (such as those with irregular shapes, colors, or intensities) by comparing measurements across multiple detector elements, and to exclude or correct readings from problematic regions while maintaining overall system simplicity.

Inventive Principle:
Principle #1Segmentation

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 solution enhances the accuracy and reliability of glucose monitoring by correcting for hematocrit and sample volume variations, ensuring precise glucose concentration measurements and minimizing user discomfort and test inefficiencies, while also improving the detection of non-ideal reaction spots.

Implementation Method 1

a surface of the assay pad or membrane is illuminated with a light source. Light is reflected from the surface of the assay pad or membrane as diffuse reflected light. This diffuse light is collected and measured

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

Chemical reagents present in the pad or membrane react with the target analyte producing a light absorbing reaction product, or color change

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Data Source

PatentEP1893994B1Analyte detection device and method with hematocrit/volume correction
Publication Date: 2019.07.24 INTUITY MEDICAL INC
  • EP1893994B1 patent drawingFigure 1
  • EP1893994B1 patent drawingFigure 2
  • EP1893994B1 patent drawingFigure 3

AI summary

An arrangement (10) for measuring the concentration of an analyte contained in a sample of body fluid includes: an assay pad (40) comprising at least one chemical reagent capable of producing a detectable signal in the form of a reaction spot (50) formed upon reaction with the analyte; a light source (32); a detector array (20); a processor (84); and a memory (80) in communication with the processor. The memory (80) includes at least one value indicative of one or more of: (i) the level of hematocrit contained in the sample; (ii) the volume of the sample applied to the assay pad; or (iii) imperfections present in the reaction spot; and further including at least one algorithm for calculating the concentration of the analyte contained in the sample. Alternatively, an arrangement (10) is described for measuring the concentration of an analyte contained in a sample of body fluid, the arrangement including: an assay pad (40) comprising at least one chemical reagent capable of producing a detectable signal in the form of a reaction spot (50) formed upon reaction with the analyte; a light source(32); a detector array (20); a processor (84); a memory (80) in communication with the processor; and at least one catalyst device constructed and arranged to be responsive to control signals.