Hemoglobin Determination in Whole Blood Using Chamber Height Variation
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Solution Overview
Problem
Current methods for determining hemoglobin concentration in whole blood samples face challenges such as high uncertainty due to scattering effects and the Segré-Silberberg effect, which can lead to inaccurate results, especially when using reflectance measurements or thin layers of blood, and often require dilution or expensive reagents.
Innovation Solution
A method and system that use absorption measurements at multiple local sample volumes at different chamber heights to create a substance concentration model, allowing for accurate determination of hemoglobin concentration without dilution, using a chamber arrangement with varying heights to minimize the Segré-Silberberg effect and avoid the need for expensive additives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If reflectance measurements are used to determine hemoglobin concentration, then the measurement can be performed on whole blood samples, but the results have high uncertainty due to scattering effects
Solution Approach 1:
The patent introduces a cuvette as an intermediary medium to hold the whole blood sample, providing a controlled optical path that minimizes scattering effects while enabling reflectance measurements. The cuvette design with specific optical properties acts as a mediator between the measurement device and the blood sample, improving measurement precision without requiring sample preparation
Solution Approach 2:
The patent changes the measurement parameters by using multiple wavelengths of light and analyzing the reflectance spectrum. By measuring at different wavelengths and applying computational algorithms to interpret the spectral data, the system achieves accurate hemoglobin concentration measurements despite scattering effects in whole blood samples
2Use of energy by moving object
If thin layers of blood are used for transmission measurements, then sufficient light transmission is achieved, but the Segré-Silberberg effect causes particle concentration changes leading to inaccurate results
Solution Approach 1:
The patent extracts the blood sample from the flow condition that causes the Segré-Silberberg effect by placing it in a stationary cuvette. This removes the harmful flow-induced particle migration while maintaining the thin layer configuration needed for adequate light transmission, thereby preserving measurement accuracy
Solution Approach 2:
The patent employs disposable cuvettes that are inexpensive and designed for single-use. These cuvettes provide the necessary thin layer geometry for transmission measurements without requiring complex reusable flow control systems, eliminating the Segré-Silberberg effect while keeping the system simple and cost-effective
3Use of energy by moving object
If dilution of the blood sample is performed to achieve sufficient light transmission, then transmission measurements can be performed, but the concentration determination becomes less accurate
Solution Approach 1:
The patent changes the optical measurement parameters by using multiple wavelengths and advanced spectral analysis algorithms. This allows the system to achieve sufficient light transmission and accurate concentration determination without diluting the sample, as the computational methods compensate for the reduced transmission in undiluted blood
4Measurement precision
If expensive reagents are used in traditional blood analysis methods, then accurate cell concentration determination is achieved, but the cost of the analysis increases
Solution Approach 1:
The patent enables the blood sample to serve itself by using its inherent optical properties for measurement. The hemoglobin in the blood naturally absorbs and reflects light at specific wavelengths, eliminating the need for external reagents that would otherwise be required to create colorimetric reactions. This self-service approach maintains measurement accuracy while removing the cost of expensive reagents
Solution Approach 2:
The patent replaces the chemical system (reagents) with an optical system (light absorption and reflectance measurements). By substituting chemical reactions with physical optical measurements, the system achieves accurate cell concentration determination without requiring expensive chemical reagents, thereby reducing the quantity of substance needed and lowering costs
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 approach provides a fast, accurate, and cost-effective method for determining hemoglobin concentration in whole blood samples, reducing errors associated with scattering and layer thickness issues, and eliminating the need for sample dilution or expensive reagents, while maintaining the accuracy of the measurement.
Implementation Method 1
The Segré-Silberberg effect result in the concentration of particles flowing in laminar flow in a tube being accumulated at a small distance to the wall due to the parabolic nature of the laminar velocity profile in the flow which produces a shear-induced inertial lift force that drives particles towards the channel walls
Implementation Method 2
measuring absorption or reflectance of light attributable to the hemoglobin in the red blood cells
Implementation Method 3
performing absorption measurements of n local sample volumes contained at different average chamber heights
Data Source
AI summary
The invention relates to a method of determining a concentration of a substance in a cell suspension, said method comprising the following steps: —determining the concentration of the substance by: —using the results of absorption measurements performed at n local sample volumes contained at different average chamber heights of a chamber arrangement comprising the cell suspension and local substance concentration in said respective local sample volumes determined based on said respective absorption measurements; —using a substance concentration model comprising local substance concentration as a function of chamber height, and—determining the substance concentration as the infinite chamber height substance concentration using said substance concentration model and the determined local substance concentrations, wherein n is at least 2, such as at least 3, such as at least 4, wherein, optionally, the cell suspension is whole blood and the substance is Hb and wherein the method further comprises determining cRBC based on the determined Hb concentration and a determined Mean Corpuscular Hemoglobin (MCH). The invention also relates to a system for executing the method.