Benefits of PCR Testing

Four Decades of PCR and Counting

PCR (polymerase chain reaction) technology celebrated its 40^th birthday last year, introduced to the world by American biochemist Kary Mullis. Over the last 40+ years, PCR technology (especially real-time PCR) has seen incredible advancements, but at its core it remains the same:

Utilizing special enzymes (e.g. polymerase); synthesized molecules (like probes and primers); and cycles of heating and cooling (aka thermal cycling); PCR tests identify the specific sequence of nucleic acids DNA/RNA) unique to a target microorganism (a virus, bacterium, parasite, etc.) in a specimen sample. The thermal cycling initiates a chain reaction that replicates (or amplifies) the target DNA/RNA exponentially until those replications reach a quantity that can be detected by the thermal cycling device (a thermal cycler, or simply a PCR instrument) which will identify the sample as being positive or negative for the presence of the target.

PCR is the Gold Standard for Infection Disease Diagnostics

The properties of sensitivity and specificity that have made PCR testing the gold standard for the diagnosis of infectious disease over the past 40 years are the reason why, for example, the user instructions for many at-home COVID-19 antigen tests recommend that a PCR test be taken following the antigen test to confirm the results, and why hospitals and physicians require a PCR test before determining a COVID-19 diagnosis.

PCR tests allow for rapid and sensitive detection of specific nucleic acid sequences. They are widely used in a variety of applications, including the diagnosis of infectious diseases. One of the main advantages of PCR is its sensitivity, which allows it to detect smaller amounts of target DNA/RNA than many other testing technologies. This makes it an ideal tool for the detection of viruses and other pathogens in a sample that may be present at low concentrations.

In addition to its sensitivity, PCR is also a highly specific technology, meaning it can accurately distinguish between different nucleic acid sequences (say, of similar but harmless pathogens) and only amplify the target sequence. This ensures that the results of a PCR test are more accurate and reliable than other technologies.

Finally, PCR tests can be used to amplify DNA from a wide range of sources, including blood, tissue, and other bodily fluids.

Real-Time PCR vs Traditional PCR vs Other Testing Technologies

Not all PCR technologies are created equal. The exact mechanics of how PCR tests function, and the countless variations that lead to better or worse outcomes, are less important than the unifying thread that binds all PCR technologies together: they can be used to create in vitro diagnostics (IVDs), identifying targets and diagnosing patients on the molecular level.

In contrast to other technologies that identify proteins that may appear in a certain structure on a particular virus, like antigen tests, or that seek to identify the antibody evidence that manifests following the body's response to an infection, PCR can identify targets earlier following infection onset and with a higher degree of accuracy than other non-molecular diagnostics. Real-time PCR can also be used to identify more targets in a single reaction (multiplexing) than isothermal technologies, which are molecular methods, but don't involve the heating and cooling cycles that characterize real-time PCR.

Most of us have probably taken a rapid response antigen test for COVID-19 in the past couple of years. At-home testing is incredibly convenient and a necessary tool to gain a level of comfort about whether you may be putting others in danger before you leave the house. Rapid antigen tests became the default option starting during the height of the pandemic. Despite efforts to make lab-quality testing free and widely available, the turnaround time on those tests left people waiting days to find out the results because the samples were sent to a centralized lab that was overwhelmed by the volume of testing required to help ensure the safety of communities around the world. At-home testing options produce results in the privacy of one's home and within just a few minutes. However, most have a limited ability to accurately detect COVID, and because they have left epidemiologists with limited ability to accurately track infection rates, some molecular diagnostics providers, like Co-Dx, have continued to work on bringing PCR technology out of labs and into homes, businesses, pharmacies, small doctors' offices, and other places where patients need accurate results right away.

PCR Tests Are More Accessible than Ever with Instruments like the Co-Dx PCR Pro

As we move forward into a world forever shaped by our collective experience with Covid-19, we are reminded that those who can't learn from their mistakes are doomed to repeat them. The importance of accurate, widespread, accessible affordable diagnoses cannot be overstated, for Covid-19 or any disease. While mistakes were certainly made as the world grappled with a once-in-a-century global healthcare crisis, the one thing that was most in-demand was the same that was the scarcest, especially during those first few months: peace of mind. The power to know, accurately and easily, whether COVID-19 had finally caught up with you or your loved ones, despite your best efforts to avoid it.

The COVID-19 pandemic drove an expansion of hospital-at-home and telehealth services, as patients took advantage of opportunities to receive care without visiting a healthcare facility. Now, this shift towards decentralization of healthcare is expanding to include PCR diagnostics, once thought to only be in the domain of highly technical labs run by trained lab technicians. New platforms and tests are in development, like the Co-Dx PCR Pro instrument and test cups, which includes a test for COVID-19 that is currently undergoing regulatory review. In addition to testing for COVID-19, at-home and point-of-care diagnostics that make it possible to detect and distinguish COVID-19 from Flu A , Flu B or RSV are in development as well. This new platform will allow PCR technology to be available in your local clinic, doctor's office, and even in your own home, providing near immediate results that give individuals and families that peace of mind, powered by gold-standard PCR technology. If we have collectively learned anything over the past 4 years, it's that this shift is not only inevitable-it's also necessary.