While centralized laboratory testing provides high-quality, high-throughput results, POC devices have the advantage of generating results at the point of need, significantly reducing the wait time.

Molecular POC systems can significantly reduce time to result. Tests can be performed where the patient sample is taken (i.e., no lengthy transport necessary), skilled scientists are not required to perform tests, and the opportunity for patient mix-up is greatly reduced as only one patient is tested at a time.

While POC systems often perform qualitative rather than quantitative tests, with COVID-19, a rapid qualitative test is sufficient to drive action by the healthcare professionals. The FDA has already approved a number of cartridge-based sample-in-answer-out POC systems including GenMark’s ePlex, Cepheid’s GeneXpert and Abbott’s ID Now.

These POC diagnostics rise to the challenge of requiring accelerated time to result, providing an optimal solution for detecting Coronavirus. However, some challenges exist with the availability of analyzers and cartridges at the point of need.

The prospect of ramping manufacturing of analyzers and their cartridges is not insignificant, nor is it an issue that is easily or quickly resolved. A great number of suppliers will need to increase their manufacturing capacity extensively in a very short timeframe.

One solution to this issue can be seen with diagnostics companies developing or augmenting their existing assay panels (molecular, immunology, or otherwise) to detect the COVID-19 virus. An example is MeMed Diagnostics, which is developing an assay for early detection of viruses (including Coronavirus) while having the ability to predict deterioration in a patient’s condition. VitaPCR (Credo Diagnostics Biomedical), BioFire (bioMérieux), QIAstat-Dx (QIAGEN) and SAMBA II (Diagnostics for the Real World) are other examples of systems and companies which have available (or under development) tests for the detection of the virus.

The advantage of developing a flexible molecular POC system is that the analyzers can serve as a platform allowing for quick expansion of a company’s test menu as the need arises. The initial analyzer that undergoes regulatory approval will have all the necessary infrastructure to allow test menu expansion in the near to mid-term future.

Once a new test panel is developed, achieving approval and time to market is greatly minimized. This lays the groundwork for rapid response and high confidence in diagnosis, in turn leading to a more responsive and effective healthcare system.

To date, molecular diagnostics has been at the forefront of COVID-19 diagnosis due to ease of development and accuracy; however, being mainly targeted at centralized laboratories, complex to perform and the long time to result has meant significant bottlenecks in testing.

A second detection methodology that has become more available for COVID-19 diagnosis at the point of need is immunoassay. This type of Point of Care test (POCT) requires more time to develop and is less sensitive, but has the advantage of being easy to manufacture, easy to use, and offers a quick time to result. Lateral flow assay formats are the most common protocol, which is the same technology used in standard home pregnancy tests. Immunoassays also provide an indication of historic viral exposure.

Immunoassays work by using IgG/IgM antibodies to detect viral antigens in patient samples. Samples can be sourced from a finger-prick of blood. An alternative method is using cloned viral antigens to detect patient antibodies against the virus. These antibodies or antigens are immobilized on a nitrocellulose membrane at particular locations. If a patient is positive for COVID-19, the interaction between antigen and antibody leads to a visible colored line appearing on the test strip.

The most common recombinant SARS-CoV-2 proteins used are nucleocapsid protein (N-protein), spike protein (S-protein) and Angiotensin-converting enzyme 2 (ACE2).

• N-protein is a structural protein that binds to the virus RNA genome, creating a shell around the enclosed nucleic acid.
• S-protein is a surface protein on the virus which mediates the attachment between virus and the host cell surface receptors. It also facilitates viral entry into the host cell by helping in the fusion of viral and host cell membranes.
• ACE2 is an endogenous membrane protein and its extracellular peptidase domain binds to receptor binding domain of S-protein.

As lateral flow tests become more available, our ability to test larger populations increases significantly. This is particularly important and impactful in remote locations and emerging nations where resources may be limited.

Throughout human history, cholera, plague, smallpox, HIV and influenza have caused several pandemics leading to fatalities in the millions. COVID-19 is the most recent global pandemic, but due to advancements in detection, treatment and vaccinations, the death toll is going to be a lot smaller than it could have been. In addition, our modern understanding of modes of transmission means governments can put in place public health measures to limit the exposure.

While the development of pharmaceuticals and vaccines are still in progress, the detection of cases is the most critical priority. Robust detection and tracking are the only ways to provide governments with the data to make informed decisions about public health, which will enable us to return as quickly as possible to the common activities of our lives.