Lateral flow reader: application fields and features

Lateral flow immunoassay technology is evolving rapidly. With a lateral flow reader, it is possible to detect colloidal gold or colored monodisperse latex particles, using charged coupled device cameras, detect fluorescent particles bases on LED excitation via confocal or another optical sensor and detect paramagnetic latexes particles.

With the integration of new reading, labeling, sample-handling, and device design come a requirement for a new approach to system development and manufacturing. That is why lateral flow readers are becoming more required in so many disciplines.

For this reason, it is essential to know the market, the fields of applications, and what are the features you should consider choosing a good reader.

Reader systems in lateral flow assays

The chemistry and biology of the lateral flow immunoassay are the essences to properly interpret the results.  Lateral flow assays must work in association with the reader and the sample-handling methodologies, being the area that provides the most fertile opportunity for assay development companies.

It is expected that market requirements will continue to drive toward integrated reader technologies for lateral flow immunoassays. Although COVID-19 has been a good driver of the lateral flow reader market, its growth expectations were already high before the last two years. In a nutshell, market drivers include the following aspects:

• The effort to push many diagnostic tests out of the central lab into the home and point of need continues. Data collection, appropriate result interpretation with minimal user error, and the new technologies in data mining are all features of that trend.
• The ability to connect assay results at the point of need with other elements of the healthcare system will centralize result interpretation, data monitoring and storage at a specific site with the possibility to provide feedback simultaneously.
• Increased sensitivity will require non-visually interpreted results, and due to their high sensitivity, they can quantify the response and give results beyond a yes/no. One example could be the traditional pregnancy test vs those that provide the number of weeks of pregnancy based on the level of human chorionic gonadotropin hormone in urine.

How to assess a lateral flow reader?

If you are assessing different readers, look deeply inside of them and follow these 4 points:

• Sensitivity: understand how the reader enhances the color of your lateral flow assay. What makes unique a lateral flow reader is its sensitivity. For example, if you are looking for a camera-based reader, elucidate how the illumination system is rather than focus your attention on the camera.
• Cost, maintenance, and mathematics: although these three words seem to do not make sense together, they are inter-connected. A lateral flow reader is a powerful tool that adds value to the lateral flow test. A reader should not be over-engineered, and it must be available with a minimum or null maintenance and calibration. Their internal algorithm test should be designed to interpret the results with an internal calibration procedure.
• Simple, robust: Its simplicity must be a prolongation of the essence of the tests. Depending on the market you address, its lightweight can be an important point.
• Communication/Connectivity: The reader should be able to collect, store, and transfer or communicate data to other sources. This will be an ultimate point that will become one of the major trends in point-of-need diagnostics in the twenty-first century.

Applications

The main fields of lateral flow reader application are nucleic acid tests, proteomics, infectious and chronic diseases. It also has other applications such as animal health, biowarfare (anthrax detection); environmental and health and safety (contaminating enzymes in manufacturing plants, air conditioning, and water quality), and agriculture & food testing (food microbiology, food allergens, mycotoxins, or genetically modified organisms’ detection and crop quality testing).