Have you ever swabbed inside your nose and used that sample to help diagnose if you have the flu or COVID-19? Or maybe you peed on a pregnancy test. The technology that makes those and other diagnostic tests like them possible is rooted in chemistry and enables people to manage their health from the privacy of their own homes.
During the COVID-19 pandemic, you may remember working and schooling from home, and getting groceries and other necessities delivered, while riding out quarantine for the weeks and even months on end. And if we believed we or somebody in our household might have been ill with COVID-19, testing kits for SARS-CoV-2 were available to diagnose the illness at the point of need.
While “point of care” refers to testing at a doctor’s office or a clinic by a medical professional, “point-of-need” refers to testing that can be done without the supervision of the care professional, usually at home. It can also be done at airports to screen passengers getting on an airplane, members of the military in preparation for deployment, and anywhere there is a need for testing results in real time performed by either the patient themselves or another lay user. Using these tests, people know whether to go to a doctor’s office to seek treatment, self-isolate, or just drink lots of fluids and get rest, all while limiting exposure to others.
Market Development As so often happens in science, advances in technology and market demand play off each other. The surge in point-of-need testing during the pandemic was no different. As consumers became more comfortable with the idea of at-home testing and even expected it, the market for it grew. At this same time, researchers expanded the types of point-of-need testing that could be offered, making them more readily available. Their availability and accessibility to consumers took a significant strain off the healthcare system, allowing doctors and nurses to focus on patients who needed care rather than testing.
In Fall 2020, MRIGlobal was contracted as part of the NIH RADx Tech program to perform analytical studies for companies seeking Emergency Use Authorization (EUA) of their COVID-19 at-home test devices. This work provided test manufacturers with the data needed to support their EUA submissions to the U.S. Food and Drug Administration or make improvements to their devices. When demand for these diagnostic tests rose in late 2021, our scientists completed studies for three device manufacturers in record time, which enabled their tests to reach the market in time for the anticipated holiday surge. To date, MRIGlobal has performed analytical studies for more than 30 manufacturers and enabled many of these companies to receive an EUA. Read more about this work at “Testing Infectious Disease Diagnostics at MRIGlobal.”
Lateral Flow Technology Diagnostic tests using lateral flow technology have been used in doctor’s offices worldwide for more than a decade, diagnosing diseases such as HIV, malaria, strep throat, and flu. Today, most point-of-need tests currently on the market are also based on lateral flow technology. While this technology was first developed for pregnancy tests, the basic chemistry behind how they work is relatively straightforward and can be applied to a wide range of target hormones, viruses, and drugs of abuse.
Lateral flow technology serves as an elegant solution to a complex problem. Essentially a laboratory on a strip of paper, they can be designed to target different analytes, such as antigens. A sample, such as urine in the case of a pregnancy test, or a swab extraction in the case of most respiratory virus tests, is placed at specific point on the paper test strip. This test strip acts like a sponge and draws the sample across it. At different points along the test strip, there are different chemistries. At the front end are the reagents, or chemicals, where the reaction is stored. As the sample flows across the surface, it will bind to a tag particle. As the sample moves further along the test strip, there will be a test line where another chemical partner has been immobilized in a line. As the target particles pass by, only the target will be trapped, resulting in a positive test if the target is present. This can be read by the presence of a colored line, whether red or blue, depending on the nature of the tagging of the particle. Unbound sample particles continue across the test strip past a control line. These particles are then trapped to indicate that the sample has made its way across the test strip and the reagents were properly released. Read about the role CRISPR played in helping to put these diagnostics in the hands of consumers when they needed them most, while keeping people safe and taking pressure off the healthcare system in “CRISPR Gene Editing.”
Developing Diagnostics The FDA has guidelines that all diagnostic device manufacturers must follow, including standardized testing to ensure their efficacy. This includes:
Limit of detection: That’s the lowest level at which a positive negative determination can be made.
Cross-reactivity: Do other viruses or bacterial organisms that might be present in a sample conflict with measuring the specific target you’re looking for?
Inclusivity: Are all the current strains of the virus picked up by the test?
Too, it is important not only that diagnostic tests pick up existing variants, but that testing is also performed to ensure that new variants are caught as they emerge. Another type of testing performed is called a flex study, which assesses what may happen if a user misuses a test or how it performs under a variety of less-than-optimal conditions, such as “Testing a SARS-CoV-2 Assay at 20,000 Feet.” These tests help ensure that the test is robust and will continue to work.
Point-of-need tests do not have to be as sensitive as a PCR test, which would be performed at the point of care or in a laboratory. Point-of-need tests are intended to be used at home by someone who is symptomatic and interested in confirming whether they are in fact positive, which can help keep healthy people out of the doctor’s office and decrease their risk of acquiring disease. For a true diagnosis, symptomatic people should still visit a doctor and get a PCR test.
Tests do not have to be limited to the most common diseases like COVID-19, influenza A, and influenza B. They can also be developed for use in tracking drugs of abuse, antimicrobial resistance, and sexually transmitted diseases. Diagnostics developers are also developing multiplex tests, which can identify multiple diseases at once. Because the symptoms for diseases like COVID-19, RSV, influenza A, and influenza B can be similar, a single multiplex test that can distinguish between the four will be very beneficial.
The Power in Point-0f-Need The power in point–of–need testing is its ability to screen populations, providing an understanding of who is sick and needs treatment and who does not. It also enables otherwise healthy people to test and remain at home, rather than going to a doctor and possibly being exposed to a disease they could have avoided. In those cases where disease does exist, the medical community is trying to control it and keep it from spreading to older and immunocompromised individuals. Point–of–need testing also provides improved access to disease testing for underserved communities, like those in rural or remote areas, who then may be able to visit a doctor in person or through telemedicine. Empowering people to better manage their care can make a significant difference in their long-term health.
Early detection using point-of-need tests allows for early disease diagnosis, which leads to early treatment and, importantly, containment, thus limiting the spread of disease.
GETTING STARTED AT MRIGLOBAL Contact MRIGlobal for further information about our work with infectious diseases. Through a multidisciplinary approach, we provide scientific and subject matter expertise for the development of medical countermeasures research against specific threats, while expanding and accelerating the delivery of high quality clinical diagnostic products.
To discuss how we can help your project be successful, contact us today.
SIGN UP FOR OUR NEWSLETTER Sign up for the MRIGlobal newsletter! It’s the best way to get the latest updates in the world of applied scientific engineering research delivered directly to your inbox.
