Molecular Diagnostics (MDx) And Lateral Flow Assays (LAFs) Dominate COVID-19 Diagnostics, Says New Report

From the technological perspective, molecular diagnostics (MDx) and lateral flow assays (LAFs) dominate COVID-19 diagnostics.

These are the latest findings of IDTechEx (Cambridge, UK), a global market research firm, that have been published in its new report "COVID-19 Diagnostics".

Diagnostic testing is possibly the only efficient way to know the spread of the SARS-CoV-2 in time and space, enabling policymakers and healthcare workers to track and mitigate the outbreak of COVID-19. The demand for COVID-19 testing is estimated to be over 600 million tests including 120 million genetic tests and over 500 million rapid tests.

Molecules derived from the virus—nucleic acids like RNA or DNA, or proteins—form the basis of diagnostics as well as being essential for developing new therapies and vaccines. Depending on the target biomarkers, the diagnostic methods can be separated into two categories: genetic testing (detecting the viral genome) and serological & antigenic testing (detecting antibodies and viral antigens, respectively). From the technological perspective, MDx and LAFs dominate COVID-19 diagnostics.

The gold standard used across clinical laboratories is quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR, MDx), which requires a central lab setting. Such qRT-PCR testing lasts for more than 2 hour and the sample shipment cost up to several days. With the demand for quicker tests at community settings, the market is moving into point-of-care (POC) devices, including POC MDx and POC LFAs.

Microfluidics is the key technology behind POC MDx, which controls the motion of small amounts of fluids in microchannels. Microfluidic cartridges enable the miniaturization of devices and introduce automation in the sample handling and detection processes. Some POC MDx devices use isothermal amplification of nucleic acid as an alternative to PCR devices. Isothermal amplification bypasses the need of thermal cycling and reduces the detection time to just five minutes. Various isothermal amplification methods have been adopted for COVID-19 diagnostics. However, complex design and unspecific amplification hinder the widespread use of this method.

Apart from the time consuming thermal cycling, real-time fluorescent detection is another limitation for low-cost and portable diagnosis tools. LAFs, electrochemical detection and microbead-based arrays are integrated with PCR to detect the amplified genetic products. These hybrid systems enable faster, cheaper and palm-size devices at the expense of sensitivity and specificity. More recently, CRISPR-Cas (gene-editing tool based on specific gene recognition) and DNA sequencing techniques show the potential for highly sensitive and selective hybrid systems.

Apart from the effort from biotech, multiple software companies have developed algorithms to identify signs of COVID-19-related pneumonia in patient scans. CT imaging is an effective way of detecting abnormalities indicative of COVID-19, and image recognition AI algorithms have the potential to detect these abnormalities faster and more efficiently than radiologists.

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