Optical Sensor Contamination Detection in Blood Measurement Chambers

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Solution Overview

Problem

Existing blood analyzers face challenges in detecting small contaminants like clots and bubbles in measurement chambers, which can cause erroneous results and waste valuable patient blood, especially in systems with small sample volumes.

Innovation Solution

A method using an optical sensor with a transparent sensor layer that detects contaminants by analyzing time-resolved luminescence data, distinguishing between intrinsic and extrinsic parameters to provide immediate feedback on contamination, utilizing reference measurements to establish a relation between these parameters for reliable detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a small measurement chamber is used to minimize blood sample volume, then the quantity of substance is improved, but the reliability deteriorates due to increased susceptibility to clot-induced blockages and measurement errors

Engineering Contradiction:
Improveblood sample volumeVSAvoidmeasurement reliability
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The system performs preliminary clot detection by analyzing the optical properties of the blood sample before the actual measurement takes place. This preliminary action identifies potential contaminants that would compromise measurement reliability, allowing for sample rejection or preprocessing before the critical measurement phase

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements continuous feedback monitoring during the measurement process by analyzing optical transmission and scattering properties. This feedback mechanism detects clots or bubbles in real-time, enabling immediate corrective actions such as extending measurement time, adjusting processing algorithms, or requesting sample replacement to maintain measurement reliability

Inventive Principle:
Principle #23Feedback

2Speed

If rapid measurement is performed to reduce time to obtaining results, then the speed is improved, but the measurement precision deteriorates due to insufficient time for proper calibration and quality control procedures

Engineering Contradiction:
Improvetime to obtaining measurement resultVSAvoidmeasurement precision
Core Design Contradiction:
SpeedVSMeasurement precision

Solution Approach 1:

Calibration and quality control procedures are performed preliminarily before patient sample analysis, establishing baseline parameters and sensor performance characteristics. This preliminary calibration enables rapid subsequent measurements without repeating full calibration sequences, maintaining precision while reducing measurement time

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system performs continuous quality monitoring and adaptive calibration during the measurement process rather than requiring separate discrete calibration steps. This continuous action maintains measurement precision throughout the rapid measurement sequence by dynamically adjusting for drift or environmental changes

Inventive Principle:
Principle #20Continuity of useful action

3Measurement precision

If thorough calibration and quality control procedures are performed to ensure accurate and precise results, then the measurement precision is improved, but the time to obtaining measurement result deteriorates

Engineering Contradiction:
Improvemeasurement precisionVSAvoidtime for calibration and quality control
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

Multiple calibration and quality control functions are merged into integrated optical measurement sequences. The same optical sensor and measurement routines used for patient sample analysis are also employed for calibration and QC, eliminating the need for separate dedicated procedures and reducing total time while maintaining precision

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system performs self-calibration and self-verification by using built-in reference standards and internal controls that are automatically measured and compared against expected values. This self-service approach eliminates time-consuming manual calibration steps while ensuring measurement precision through automated quality assurance

Inventive Principle:
Principle #25Self-service

4Reliability

If conventional clot detection methods are used to monitor filling and discharge procedures, then the reliability is improved for detecting flow-blocking clots, but the measurement precision deteriorates for detecting small contaminants that do not affect flow

Engineering Contradiction:
Improveclot detection reliabilityVSAvoidcontaminant detection precision
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

Optical properties serve as an intermediary measurement parameter that indirectly detects the presence and characteristics of clots and bubbles. By measuring light transmission and scattering properties, the system can identify contaminants based on their optical signatures rather than relying solely on their mechanical impact on fluid flow, enabling detection of both flow-blocking and non-flow-blocking contaminants with high precision

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enables rapid and reliable detection of contaminants, ensuring accurate measurements and preventing waste of valuable samples by providing instant corrective actions, particularly crucial in emergency or intensive care scenarios.

Implementation Method 1

The sensor layer comprises a luminophor and instrumentation is provided for detecting luminescence radiation emitted from the sensor layer in response to the applied stimulus

Methodology Applied
Scientific EffectLuminescence: Luminescence

Implementation Method 2

instrumentation is provided for detecting luminescence radiation emitted from the sensor layer in response to the applied stimulus

Methodology Applied
Scientific EffectOptical detection:

Implementation Method 3

A method using an optical sensor with a transparent sensor layer that detects contaminants by analyzing time-resolved luminescence data

Methodology Applied
Scientific EffectTime-resolved luminescence detection:

Data Source

PatentEP3729055B1Method and sensor for detecting presence or absence of a contaminant
Publication Date: 2025.11.05 RADIOMETER AS
  • EP3729055B1 patent drawingFigure 1
  • EP3729055B1 patent drawingFigure 2~3
  • EP3729055B1 patent drawingFigure 4

AI summary

The present invention relates in one aspect to a method of detecting a contaminant in a measurement chamber (201) of a sample analyzer (200). The sample analyzer (200) comprises an optical sensor with a sensor layer (205) comprising a luminophor (201), wherein the sensor layer (205) has a sensor surface (206) forming an interface to the measurement chamber (201). The method comprises steps of: filling the measurement chamber with a fluid sample; applying a stimulus to the luminophor in the sensor layer; detecting luminescence emitted from the luminophor in the sensor layer in response to the stimulus as a function of time; obtaining a time sequence of measurement values for the detected luminescence; based on the time sequence, determining an actual value of a first parameter and an actual value of a second parameter, wherein one of the first and second parameters is sensitive to a change in refractive index across the interface between the sensor layer and the measurement chamber, and wherein the other one of the first and second parameters is not sensitive to said change in refractive index across the interface between the sensor layer and the measurement chamber; developing an expected value for the second parameter based on the actual value of the first parameter; comparing the expected value for the second parameter to the actual value of the second parameter; and determining the presence (or absence) of a contaminant based on the comparison. In a further aspect, a sample analyzer configured for detecting contaminants in the measurement chamber using embodiments of the above method is provided.