Dual-Test-Line Pregnancy Device Resolving Hook Effect
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Solution Overview
Problem
Current pregnancy diagnostic kits experience false negative results due to the hook phenomenon and interference from high concentrations of human chorionic gonadotropin (hCG) and its beta-core fragment (βcf hCG), leading to potential medical misdiagnoses and accidents.
Innovation Solution
Incorporating a second test line specifically for detecting βcf hCG, in addition to the standard test line for I-hCG, using antibodies that do not interfere with each other, allowing for accurate pregnancy diagnosis by detecting βcf hCG even in high concentrations of I-hCG, thereby minimizing false negative results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single test line detecting I-hCG is used, then the diagnostic simplicity is maintained, but false negative results occur due to the hook effect at high I-hCG concentrations
Solution Approach 1:
The patent divides the diagnostic function into two separate test lines: one for detecting intact hCG (I-hCG) and another for detecting beta-core fragment hCG (βcf hCG). This segmentation allows each test line to operate independently, avoiding the hook effect interference that occurs in single-test-line systems when I-hCG concentration is high. The segmentation principle resolves the contradiction by maintaining diagnostic simplicity (single strip format) while improving reliability through dual-detection capability.
2Device complexity
If only I-hCG detection is performed, then the test design is simple, but false negatives occur when I-hCG concentration exceeds antibody binding capacity
Solution Approach 1:
The diagnostic strip is segmented into two functional test lines with distinct detection targets. The first test line detects I-hCG using anti-I-hCG antibodies, while the second test line detects βcf hCG using anti-βcf hCG antibodies. This segmentation enables the system to maintain simple test design (single strip format) while achieving high measurement precision by detecting hCG through multiple pathways that do not interfere with each other.
Solution Approach 2:
The patent introduces βcf hCG detection as an intermediary mechanism to resolve the limitation of I-hCG detection. When I-hCG concentration is high and causes hook effect (saturation of detection antibodies), the βcf hCG detection line serves as an alternative pathway to confirm pregnancy status. This intermediary detection method resolves the contradiction by maintaining simple test design while improving detection accuracy through complementary detection strategies.
3Reliability
If a dual test line system is implemented, then false negative reduction is achieved, but the device complexity increases
Solution Approach 1:
The patent implements segmentation by creating two distinct test lines on a single diagnostic strip, each with its own specific antibodies and detection mechanisms. This segmentation approach reduces false negatives by providing multiple detection pathways while managing device complexity through integrated strip design. The segmentation allows parallel detection of I-hCG and βcf hCG without requiring separate test devices, thus improving reliability with minimal increase in overall system complexity.
Solution Approach 2:
The diagnostic strip is designed with multi-functionality by incorporating both I-hCG and βcf hCG detection capabilities in a single device. This universality allows the test strip to perform multiple detection functions simultaneously, reducing false negatives through complementary detection while avoiding the complexity of requiring separate test devices. The multi-functional design resolves the contradiction by achieving enhanced reliability within a unified, manageable device structure.
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 dual-test-line approach effectively reduces false negative results by detecting βcf hCG, ensuring accurate pregnancy diagnosis and extending the diagnostic range beyond limitations of single-test-line kits, improving overall diagnostic accuracy.
Implementation Method 1
an anti-I-hCG antibody which specifically recognizes intact hCG (I-hCG) and an anti-βcf hCG antibody which specifically recognizes beta-core fragment hCG (βcf hCG)
Data Source
AI summary
An immune device for pregnancy diagnosis of the inventive concept includes a sample region for receiving a test sample to be analyzed; a conjugate region connected to the sample region and including an anti-I-hCG antibody conjugated with a probe and an anti-βcf hCG antibody conjugated with a probe; a signal detection region connected with the conjugate region, wherein the signal detection region includes a first test line having an anti-I-hCG antibody immobilized to the first test line, a second test line having an anti-βcf hCG antibody immobilized to the second test line, and a control line; and a wicking region located downstream of the signal detection region, wherein the wicking region absorbs the test sample for which a signal detection reaction has terminated.