Flow Cytometer Polarization Discrimination Erythrocyte Crystal Overlap

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Solution Overview

Problem

Conventional methods for analyzing urine samples using flow cytometers face challenges in accurately distinguishing and counting erythrocytes from crystals due to overlapping distribution regions, which affects the reliability and precision of erythrocyte counting, especially in samples containing high numbers of crystals.

Innovation Solution

A sample analyzing method that involves flowing a mixed sample and reagent through a flow cell, irradiating particles with linearly polarized light to produce scattered light, detecting changes in polarization conditions, and discriminating erythrocytes from crystals based on these changes, allowing for accurate counting even in samples with numerous crystals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional flow cytometry methods are used to detect particles in urine samples, then the distribution regions of erythrocytes and crystals can be plotted on a two-dimensional distribution diagram, but the distribution regions of erythrocytes and crystals overlap, reducing the reliability and precision of erythrocyte counting

Engineering Contradiction:
Improveerythrocyte counting precisionVSAvoidclassification reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent introduces a new detection dimension by measuring the polarization state of scattered light in addition to conventional forward scattered light and fluorescent light. This adds a third parameter space for particle discrimination, allowing erythrocytes and crystals to be distinguished even when their distributions overlap in conventional two-dimensional plots. The polarization parameter creates a new axis of differentiation that resolves the overlap problem.

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

Solution Approach 2:

The patent changes the physical parameter being measured from conventional intensity-based detection to polarization-state-based detection. By measuring how scattered light's polarization state changes upon interaction with particles, the method exploits fundamental differences in optical properties between erythrocytes and crystals, enabling reliable discrimination regardless of particle concentration or size variations.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If the number of crystals in urine samples is high, then the distribution regions of erythrocytes and crystals overlap more significantly, but accurate erythrocyte counting remains essential for diagnosing renal and urinary tract diseases

Engineering Contradiction:
Improvecrystal concentrationVSAvoiderythrocyte counting accuracy
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent uses polarization state as an intermediary property to indirectly distinguish erythrocytes from crystals. Instead of directly measuring particle identity, the method measures how each particle type modifies the polarization state of scattered light, using this intermediate measurement as a reliable proxy for particle classification even in high-crystal-concentration samples.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If conventional light detection methods are used, then particles can be detected based on forward scattered light and fluorescent light intensity, but erythrocytes and crystals cannot be reliably distinguished due to distribution overlap

Engineering Contradiction:
Improveparticle detection efficiencyVSAvoidparticle discrimination accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent makes the flow cytometer multi-functional by adding polarization detection capability to the existing forward scattered light and fluorescent light detection systems. This allows the same instrument to perform both conventional particle detection and new polarization-based discrimination, maintaining productivity while improving discrimination accuracy through integrated multi-parameter analysis.

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

This method enables precise discrimination and counting of erythrocytes and crystals, improving the accuracy of erythrocyte counting and providing valuable information for diagnosing renal and urinary tract diseases by effectively distinguishing between the two based on polarization changes.

Implementation Method 1

irradiating particles in the measurement specimen flowing through the flow cell with linearly polarized light and thereby producing scattered light

Methodology Applied
Scientific EffectLight scattering: Scattering

Implementation Method 2

detecting a change of polarization condition of the scattered light produced by the particles

Methodology Applied
Scientific EffectPolarization: Polarisation

Data Source

PatentEP2843410B1Sample analyzing method and sample analyzer
Publication Date: 2017.10.11 SYSMEX CORP
  • EP2843410B1 patent drawingFigure 1
  • EP2843410B1 patent drawingFigure 2
  • EP2843410B1 patent drawingFigure 3

AI summary

Disclosed is a sample analyzing method comprising: flowing a measurement specimen prepared by mixing a sample and reagent through a flow cell; irradiating particles in the measurement specimen flowing through the flow cell with linearly polarized light and thereby producing scattered light; detecting a change of polarization condition of the scattered light produced by the particles; and discriminating erythrocytes from crystals in the measurement specimen based on the change of polarization condition.