Lateral Flow Test Reading with Cassette-Based Optical Normalization
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Solution Overview
Problem
Existing lateral flow tests require expensive motorized readers for accurate results, which are not readily accessible to patients, and existing manual readers rely on additional calibration patterns that complicate the reading process.
Innovation Solution
A method for reading lateral flow tests using a cassette with a known color difference between the cassette and test strip, allowing direct normalization of luminous intensity values without additional calibration patterns, using a reader with a light emitter and sensor to identify peaks corresponding to test and control lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If motorized readers with optical units are used for accurate lateral flow test reading, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the calibration function from a separate calibration pattern and integrates it into the test strip design itself. The test strip includes a calibration region with known optical properties that serves dual purposes: as part of the test structure and as the calibration reference. This eliminates the need for separate calibration components while maintaining reading accuracy.
Solution Approach 2:
The test strip is designed to serve multiple functions: it performs the diagnostic test function and simultaneously provides the calibration reference function. The calibration region on the test strip acts as both a structural element of the test device and a reference standard for optical measurement, allowing a single component to fulfill multiple roles in the reading system.
2Measurement precision
If separate calibration patterns are added to enable accurate reading, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the calibration pattern with the test strip structure itself. The calibration region is integrated into the test strip as a unified component rather than being a separate element. This combination allows the test strip to provide both the test functionality and the calibration reference in a single integrated device, simplifying the overall system.
3Ease of operation
If manual cassette movement is used in reader, then ease of operation is improved, but measurement precision deteriorates
Solution Approach 1:
The patent prepares the calibration reference in advance by incorporating it directly into the test strip structure before the testing process begins. The calibration region with known optical properties is pre-positioned and ready for use, eliminating the need for dynamic calibration adjustments during manual operation. This preliminary preparation ensures that accurate measurements can be obtained even with manual cassette movement.
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 rapid, accurate, and cost-effective detection of analytes in biological samples using a manual reader, eliminating the need for additional calibration and reducing the time to results from hours to minutes.
Implementation Method 1
a reader that has a housing for receiving the cassette, the reader having an optical unit with a light emitter for illuminating the cassette and a sensor for receiving the light reflected by the cassette
Implementation Method 2
the sample is diffused by capillarity along the test strip
Data Source
Figure 1a~1b
Figure 2~3
Figure 4a
AI summary
Reading method of a lateral flow test using a cassette and a reader, the cassette having a window through which there is observed a test strip, wherein there is a reactive zone with a test line and a control line, and the reader has a light emitter for illuminating the cassette and a sensor for receiving the light reflected by the cassette, the method comprises manually moving the cassette and obtaining a signal of the light reflected by the cassette, normalizing the signal in a range defined between a lower value and a higher value, and identifying peaks in the signal corresponding with the test and control lines, wherein the lower value and the higher value are established between the light reflected by the cassette outside the and the light reflected by the test strip outside the reactive zone.