Lateral Flow Immunoassay for Simultaneous Hemoglobin and Transferrin Detection
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Solution Overview
Problem
Current fecal occult blood (FOB) tests face challenges such as limited sensitivity, requirement for strict diet control, sample degradation issues, and lack of reliable automated analyzers for fecal samples, making it difficult to accurately differentiate between upper and lower gastrointestinal bleeding.
Innovation Solution
A method using a lateral flow immunoassay device to simultaneously detect hemoglobin and transferrin in fecal samples, with predetermined values for differential diagnosis between upper and lower GI tract bleeding, employing labeled antibodies and gold particles on a nitrocellulose test strip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a chemical test using guaiac substrate is employed to detect hemoglobin metabolites, then the test can be performed with simple reagents, but the test sensitivity is limited (50 μg/ml) and diet control is required for specificity
Solution Approach 1:
The patent combines multiple detection targets (hemoglobin and transferrin) into a single test system. The test strip includes multiple test zones that can simultaneously detect different biomarkers, allowing the system to overcome the limitations of single-target chemical tests while eliminating the need for strict diet control through multiple specific antibody reactions
Solution Approach 2:
The patent replaces the chemical reaction-based guaiac test with an immunoassay system using antibodies and labeled particles. This substitution enables higher sensitivity detection (down to 5 μg/ml or lower) without requiring dietary restrictions, as the antibody-based detection is more specific and less interfered by food substances
2Measurement precision
If an immunoassay for hemoglobin is used to improve sensitivity and eliminate diet control, then test sensitivity and specificity are improved, but hemoglobin degrades rapidly in the GI system and during storage
Solution Approach 1:
The patent makes the test system universal by detecting multiple stable biomarkers (hemoglobin, transferrin, and potentially other markers) simultaneously. This multi-target approach ensures that even if one marker degrades, others can still provide reliable detection, thereby maintaining high sensitivity and specificity while accommodating the instability of hemoglobin
Solution Approach 2:
The patent performs detection immediately upon sample application to the test strip, before significant degradation can occur. The rapid capillary flow and immediate antibody-antigen reaction minimize the time hemoglobin remains in the sample, preserving its detectability while allowing for rapid results
3Ease of operation
If a single biomarker test is used, then the test is simple and rapid, but the ability to differentiate between upper and lower GI bleeding is limited
Solution Approach 1:
The patent segments the detection function into multiple distinct test zones on a single strip, each targeting different biomarkers associated with specific GI regions. This segmentation allows simultaneous detection of upper GI (transferrin) and lower GI (hemoglobin) bleeding sources while maintaining the simplicity of a single-drop sample application
Solution Approach 2:
The patent adds a diagnostic dimension by incorporating multiple biomarkers that provide spatial information about bleeding location. The pattern of positive results across different test zones (e.g., transferrin positive but hemoglobin negative suggests upper GI bleeding) enables differentiation without complicating the user interface or sample collection
4Ease of operation
If fecal samples are collected and stored for later analysis, then sampling can be done at convenient times, but sample degradation affects test accuracy
Solution Approach 1:
The patent performs the detection action immediately upon sample application to the test strip, before degradation can significantly affect accuracy. The rapid capillary flow and immediate antibody-antigen reaction minimize the time hemoglobin remains in the sample, preserving its detectability while allowing for rapid results
Solution Approach 2:
The patent uses multiple biomarkers with different stability characteristics (transferrin being more stable than hemoglobin) to compensate for sample degradation. By detecting both markers, the system can maintain accuracy even when samples are not immediately processed, as the more stable transferrin can provide reliable detection signals
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
Improves test sensitivity and specificity by stabilizing the detection of occult blood markers, reducing false negatives, and providing a rapid onsite testing solution for GI bleeding differentiation.
Implementation Method 1
A method using a lateral flow immunoassay device to simultaneously detect hemoglobin and transferrin in fecal samples
Implementation Method 2
employing labeled antibodies and gold particles on a nitrocellulose test strip
Data Source
Figure 1A~1B
Figure 2~6
AI summary
The present invention relates generally to detection of occult blood. In particular, the present invention provides a device and methods for the simultaneous detection of hemoglobin and transferrin in fecal samples, which permit a more sensitive diagnosis of occult blood in fecal sample and a differential diagnosis of bleeding of the upper GI tract versus the lower GI tract.