Glucose Calibration Using Capillary-to-Venous Conversion

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Solution Overview

Problem

Current glucose monitoring systems face challenges in accurately calibrating calculated glucose levels using impractical venous blood glucose measurements, leading to inaccuracies in glycemic control for diabetes management.

Innovation Solution

A system that utilizes capillary blood glucose measurements as reference to calibrate calculated glucose levels, converting them to venous blood glucose levels through a model that minimizes errors by using a cost function to estimate venous levels based on experimental data, enabling more accurate glucose monitoring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If venous blood glucose measurements are used for calibration, then measurement precision is improved, but ease of operation deteriorates due to impracticality

Engineering Contradiction:
Improveglucose level accuracyVSAvoidcalibration practicality
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent uses capillary blood glucose measurements as an intermediary to bridge the gap between practical measurements and the ideal venous blood glucose reference. The system accepts easily obtainable capillary measurements from users and uses conversion algorithms to estimate corresponding venous blood glucose levels, thereby maintaining measurement precision without sacrificing ease of operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system creates a virtual copy of venous blood glucose measurements by converting capillary blood glucose readings. Instead of directly measuring impractical venous samples, the system generates estimated venous glucose values through mathematical conversion, preserving the benefits of venous reference accuracy while using practical capillary sampling.

Inventive Principle:
Principle #26Copying

2Ease of operation

If capillary blood glucose measurements are used for calibration, then ease of operation is improved, but measurement precision deteriorates due to differences between capillary and venous glucose levels

Engineering Contradiction:
Improvecalibration practicalityVSAvoidglucose level accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The system applies parameter transformation by converting capillary blood glucose measurements to estimated venous blood glucose levels using physiological conversion factors. This parameter change accounts for the natural differences between capillary and venous glucose concentrations, thereby maintaining measurement precision while preserving the ease of capillary sampling.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical/biological process of directly measuring venous blood with a computational substitution. Instead of physically obtaining venous samples, the system uses mathematical models and conversion algorithms to calculate equivalent venous glucose levels from capillary measurements, achieving the same calibration objective through computational rather than physical means.

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

3Productivity

If finger-stick glucose tests are used frequently, then measurement frequency is improved, but loss of time increases due to burden on patients

Engineering Contradiction:
Improvemeasurement frequencyVSAvoidpatient time burden
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The system replaces the mechanical finger-stick testing process with a continuous electrochemical sensor that measures glucose in interstitial fluid. This substitution eliminates the need for repeated manual blood sampling, allowing continuous monitoring without the time burden of frequent finger-sticks while maintaining high measurement frequency.

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

Solution Approach 2:

The patent implements continuous glucose monitoring that provides uninterrupted glucose level data without requiring periodic interruption for finger-stick tests. The sensor continuously measures interstitial glucose, delivering a steady stream of useful information without the time loss associated with discrete manual sampling events.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP4335368B1Systems for reducing difference between calculated and measured analyte levels
Publication Date: 2026.04.15 SENSEONICS INC
  • EP4335368B1 patent drawingFigure 1
  • EP4335368B1 patent drawingFigure 2
  • EP4335368B1 patent drawingFigure 3

AI summary

Systems, methods, and apparatuses for reducing error between calculated analyte levels and impractical analyte measurements using practical analyte measurements as reference measurements for calibration. Reducing the error may include converting a practical reference analyte measurement into an estimated impractical analyte level, updating a conversion function using the estimated impractical analyte level, and using the updated conversion function to calculate an analyte level. In some aspects, the practical reference analyte measurement may be a capillary blood analyte measurement, and the estimated impractical analyte level may be an estimated venous blood analyte level. In some aspects, the updated conversion function may minimize the error between analyte levels calculated using the updated conversion function and estimated venous blood analyte levels.