Hydroxyethyl Starch Additive for Immunochromatographic Measurement Accuracy

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Solution Overview

Problem

The immunochromatographic method faces deviations in measurement values when using undiluted blood specimens as samples, especially when analyte concentrations exceed the upper limit of quantitation, leading to inaccurate results.

Innovation Solution

Incorporating hydroxyethyl starch (HES) into the immunochromatographic device or blood specimen diluent to reduce deviations in measurement values, allowing for accurate quantitation even with diluted samples.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a diluted blood specimen is used as a sample when analyte concentration exceeds upper limit of quantitation, then the measurement system can handle high concentration samples, but deviations from theoretical values occur and measurement accuracy deteriorates

Engineering Contradiction:
Improveability to handle high concentration samplesVSAvoidaccuracy of measurement values
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

Hydroxyethyl starch acts as an intermediary substance that mediates between the diluted blood specimen and the immunochromatographic measurement system. It is incorporated into the measurement system (in the membrane or conjugate pad) to prevent direct adverse interactions between the diluted sample and the assay components, thereby reducing measurement deviations while maintaining the ability to handle high concentration samples through dilution

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the compositional parameters of the measurement system by incorporating hydroxyethyl starch at specific concentrations (0.1-10% by mass in the membrane, or 0.01-1% in the conjugate pad). This parameter change modifies the measurement environment to reduce deviations from theoretical values when diluted blood specimens are used, thereby improving measurement accuracy

Inventive Principle:
Principle #35Parameter changes

2Productivity

If nonionic water-soluble polymer with molecular weight greater than 9000 is used as reaction accelerator, then reaction-accelerating effect is sufficient, but spreadability of tested solution deteriorates and detection time increases

Engineering Contradiction:
Improvereaction acceleration effectVSAvoidtime required for achieving constant color development
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The invention changes the molecular weight parameter of the nonionic water-soluble polymer from greater than 9000 to between 2000 and 9000. This parameter optimization maintains sufficient reaction-accelerating effect while improving spreadability of the tested solution, thereby reducing the time required to achieve constant color development in the detection site

Inventive Principle:
Principle #35Parameter changes

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

The use of hydroxyethyl starch suppresses deviations from theoretical values, enabling accurate measurements with diluted blood specimens, thus preventing reductions in measurement accuracy.

Implementation Method 1

when measurement is performed in the presence of hydroxyethyl starch at the time of measurement of a diluted blood specimen in a non-dilution method, the deviation from the theoretical value can be reduced

Methodology Applied
Scientific EffectHydroxyethyl starch interaction:

Data Source

PatentEP2902783B1Additive for measuring diluted sample in non-dilution-type immunochromatographic method reagent
Publication Date: 2017.08.30 SEKISUI MEDICAL CO LTD
  • EP2902783B1 patent drawingFigure 1~2
  • EP2902783B1 patent drawing

AI summary

Provided are: an immunoassay method in which the deviation from a theoretical value (hereinafter also referred to as "a reference value"), which may be caused when a diluted blood specimen is used as a sample, is reduced in an immunochromatographic method that is so designed that a blood specimen (whole blood, serum or plasma) is used directly as a sample without subjecting the blood specimen to any pretreatment such as a dilution treatment; and a reagent for use in the method. An immunochromatographic method performed on a blood specimen using an immunochromatographic device equipped with (1) a sample pad and (2) a membrane on which a component capable of specifically binding to an analyte is immobilized, arranged in the order of (1) and (2) from upstream, wherein hydroxyethyl starch is present in the measurement system.