Blood Analyzer Plasma Correction for Hemoglobin Interference

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Solution Overview

Problem

Existing blood gas analyzers struggle to accurately measure hemoglobin forms in the presence of unknown extracellular interferents without requiring field notices, sample studies, verification studies, and software updates.

Innovation Solution

A blood analyzer that separates plasma from whole blood, measures the absorbance of both plasma and lysed blood samples, and adjusts the total absorbance spectrum to remove the effects of unknown extracellular interferents in real time, using a dispensing device, plasma separator, and lysis device to obtain accurate hemoglobin form concentrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional optical measurement is used to determine hemoglobin forms, then measurement simplicity is maintained, but measurement precision deteriorates due to interference from unknown extracellular substances

Engineering Contradiction:
Improveaccuracy of hemoglobin form measurementVSAvoidcomplexity of measurement system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The blood sample is divided into two separate measurement components: plasma (containing extracellular interferents) and lysed blood (containing hemoglobin forms). By measuring these components separately and mathematically combining the results, the system achieves accurate hemoglobin measurement while eliminating plasma interference, without requiring complex real-time interference subtraction algorithms

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The plasma containing unknown extracellular interferents is extracted and measured separately from the cellular blood components. This extraction allows the interferent spectrum to be obtained independently, which is then subtracted from the total blood sample spectrum to isolate the hemoglobin signal, thereby improving measurement precision

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If lysed blood measurement is used to eliminate light scatter, then measurement reliability improves, but reliability deteriorates due to unknown extracellular interferents affecting the measurement

Engineering Contradiction:
Improveconsistency of measurementVSAvoidinterference from extracellular substances
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A plasma sample measurement serves as an intermediary step that captures the interference spectrum from extracellular substances. This intermediary measurement is then used to correct the lysed blood measurement by subtracting the plasma spectrum, thereby eliminating the harmful interference while maintaining measurement reliability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The plasma sample is measured preliminarily before the lysed blood measurement to establish the baseline interference spectrum. This preliminary action allows the system to pre-calculate the correction factor needed to eliminate extracellular interferent effects from the subsequent hemoglobin measurement

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If plasma separation and dual measurement is implemented, then measurement precision improves by removing interferent effects, but device complexity increases due to additional components

Engineering Contradiction:
Improveaccuracy of hemoglobin concentration determinationVSAvoidnumber of measurement components
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The optical measurement system is designed to universally measure both plasma samples and lysed blood samples using the same light source and detector configuration. This multi-functionality allows the system to obtain both the interference spectrum and the hemoglobin spectrum without requiring separate specialized measurement devices, thereby managing complexity while improving precision

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

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 accurate determination of hemoglobin forms by effectively canceling out the influence of unknown extracellular interferents, eliminating the need for additional studies and software updates, and ensuring precise measurement results.

Implementation Method 1

The light source emits broadband light into the input region into the sample-reagent combination inside the vessel. A chemical reaction of the sample-reagent combination produces chromophores absorbing light at specific wavelengths proportional to the concentration of the analyte being measured.

Methodology Applied
Scientific EffectAbsorption spectroscopy: Absorption Spectroscopy

Implementation Method 2

The detector obtains an absorbance measurement of the emitted light signal at specific wavelengths following the Beer-Lambert law

Methodology Applied
Scientific EffectBeer-Lambert law: Absorption (EM radiation)

Implementation Method 3

a plasma separator to separate plasma from a blood sample

Methodology Applied
Scientific EffectPlasma separation: Centrifugal Separation

Implementation Method 4

Some devices lyse the red blood cells using ultrasound. Some point-of-care testing devices use spectrophotometric optical absorption measurement for the determination of the oximetry parameters on a whole blood sample.

Methodology Applied
Scientific EffectLysis: Acoustic Cavitation

Data Source

PatentEP4164490B1Method and analyzer to correct for unknown interferences in a patient blood sample
Publication Date: 2026.01.07 SIEMENS HEALTHCARE DIAGNOSTICS INC
  • EP4164490B1 patent drawingFigure 1
  • EP4164490B1 patent drawingFigure 2
  • EP4164490B1 patent drawingFigure 3

AI summary

Analyzers and methods of use are disclosed, including a blood analyzer comprising a light source to transmit an optical signal; a detector to generate data indicative of optical signal intensity; a transparent sample vessel between the light source and the detector; a dispensing device to pass a first portion of the blood sample comprising whole blood or lysed blood into the vessel at a first instance of time, and to pass a plasma portion of the blood sample into the vessel at a second instance of time; a controller to cause a processor to obtain first and second data generated by the detector, the first data indicative of the optical signal passing through the first portion of the blood sample and the second data indicative of the optical signal passing through the plasma, to determine a total absorbance spectrum in which the first data is adjusted by the second data.