An Optimized Colorimetric Readout Method for Lateral Flow Immunoassays

Abstract

Despite its broad penetration of various markets, the quantitative lateral flow immunoassay (LFIA) suffers from sensitivity issues in some cases. To solve this problem, an optimized colorimetric readout method for LFIA quantification is proposed in this study. An assay reader device utilizing a color camera and an analysis method using a Bayer filtered image were developed. Spectrometric measurements of the assay test line were performed to determine the color channel that contains the test line information and effectively minimizes noise. The change in the intensity ratio with increasing concentration of the target substance in the sample was largest in the green channel. The linear range of the output curve ranged from 0 to 10 ng/mL, and the detection limit was 2 ng/mL. The suggested instrumentation and analysis methods are expected to effectively resolve the low-sensitivity problems of the former LFIA systems and to offer other prospective functionalities for LFIA quantification.

An Overview for the Nanoparticles‐Based Quantitative Lateral Flow Assay

“…Reproduced with permission. [ 106 ] Copyright 2018, MDPI. c) Multicolored disease diagnostic platform: i,ii) TIDBIT reader overview showing components and internal structures of the device, iii) LFA strips, iv) assembled integrated fluorescence sensor.…”

“…For colorimetric measurements, the color intensities (such as, the gray value or RGB coordinates) of the T and C lines are collected with the imaging system or scanning system of the reader device. In the process of strip testing, the light reflected from the test zone is received by a reflective measurement sensor and registered as a digital signal [ 106 ] (Figure 8b). The testing process for fluorescence measurements is similar to that for colorimetric measurements, with the only difference that the reader contains a fluorescence sensor rather than a reflective measurement sensor.…”

A new point-of-care test for the diagnosis of infectious diseases based on multiplex lateral flow immunoassays

“…cameras, spectrometers, and magneto-inductive sensors). 44,45 On the other hand, their performances have yet to be sufficient enough for use in settings of developed countries. To this end, we suggest that improvements to the next steps should be considered to prove the stability of the assays, ease of fabrication of the platforms, and practicality in emergency use.…”

A Point-of-Care Measurement of NT-proBNP for Heart Failure Patients

“…The 'Profile-plot' tool was used to measure the peak amplitude of the test line in greyscale values with reference to the background greyscale value of the non-test line region of the membrane. This is an established method for deriving a quantitative output from LFIA test strips [41]- [43]. Its previous and common usage makes it useful as a 'reference' measurement method to which we can compare results from the biomarker analyser.…”