Fluorescent Cell Staining for Low-Count Body Fluid Analysis

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Solution Overview

Problem

Traditional hematology analyzers have limited detection sensitivity for low cell concentrations in body fluids, making it difficult to analyze samples with fewer than 20 cells/µL, and often require manual examination, which is inefficient and prone to inaccuracies.

Innovation Solution

A method involving the use of a fluorescent dye that permeates cell membranes and binds to nucleic acids, allowing for differentiation and enumeration of cells through fluorescence measurement, using an automated analyzer or flow cytometer without lysing red blood cells, and utilizing a composition that includes water and the dye to enhance sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional hematology analyzers are used to analyze body fluids, then the analysis can be performed automatically, but the detection sensitivity is limited for low cell concentrations (fewer than 20 cells/µL)

Engineering Contradiction:
Improvedetection sensitivityVSAvoidanalysis capability
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the detection parameter from traditional light scattering to fluorescence emission. By using fluorescent dyes that bind to nucleic acids and emit fluorescence signals, the system achieves much higher detection sensitivity for low cell concentrations. The fluorescence signal provides a stronger and more detectable response compared to traditional methods, enabling accurate measurement of samples with fewer than 20 cells/µL.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If manual examination is used to analyze low cell count samples, then detection sensitivity can be improved, but the analysis becomes inefficient and prone to inaccuracies

Engineering Contradiction:
Improvedetection sensitivityVSAvoidanalysis efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent replaces the manual mechanical examination process with an automated fluorescence-based detection system. The automated analyzer uses fluorescent dyes and light sources to detect and count cells, eliminating the need for manual microscopy while maintaining high detection sensitivity. This substitution preserves the accuracy benefits of careful examination while achieving high throughput and consistency through automation.

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

3Measurement precision

If fluorescent dyes are used to stain body fluids, then cell differentiation and enumeration sensitivity is improved, but the sample preparation complexity increases

Engineering Contradiction:
Improvecell differentiation accuracyVSAvoidsample preparation
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts and utilizes the natural nucleic acid content within cells as the target for fluorescence staining. By using dyes that specifically bind to nucleic acids (DNA/RNA) present in all cells, the method achieves universal cell detection and differentiation without requiring complex sample preparation steps. The nucleic acid serves as an inherent marker that simplifies the staining process compared to methods requiring external markers or complex protocols.

Inventive Principle:
Principle #2Taking out (Extraction)

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 and efficient analysis of body fluids with low cell counts, including those with fewer than 20 cells/µL, by differentiating and enumerating cells based on fluorescence signals, improving diagnostic accuracy and reducing sample preparation complexity.

Implementation Method 1

the fluorescent dye permeates a cell membrane and binds to a nucleic acid

Methodology Applied
Scientific EffectPermeation: Permeation

Implementation Method 2

binds to a nucleic acid to form a dye complex within the cell

Methodology Applied
Scientific EffectBinding: Chemical Bonding

Implementation Method 3

irradiating the stained body fluid with energy from an energy source; and measuring a fluorescence signal emitted by the dye complex

Methodology Applied
Scientific EffectFluorescence excitation: Fluorescence

Implementation Method 4

measuring a fluorescence signal emitted by the dye complex in the stained body fluid

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Data Source

PatentEP3382035B1Cellular analysis of body fluids
Publication Date: 2021.08.11 ABBOTT LAB INC
  • EP3382035B1 patent drawingFigure 1
  • EP3382035B1 patent drawingFigure 2A
  • EP3382035B1 patent drawingFigure 2B

AI summary

Herein is provided a simple, reliable and accurate method for cellular analysis on hematology analyzers. In various aspects, the methods provide separation and/or differentiation between red blood cells (RBCs) and white blood cells (WBCs) by utilizing a fluorescent dye to selectively stain WBCs such that they emit stronger fluorescence signals. The method provides optimal detection limits on WBCs and RBCs, thereby allowing analysis of samples with sparse cellular concentrations. As few as one reagent may be used to prepare a single dilution for body fluid analysis, in order to simplify the body fluid analysis. Minimal damage to WBCs is attained using the lysis-free approach described in aspects of the disclosure.