Upper respiratory tract infections are one of the top three diagnoses in the outpatient setting, accounting for an estimated 10 million appointments in the U.S. each year [1]. Getting patients the right treatment as quickly as possible is essential for reducing this burden, both economically and socially; however, accurately diagnosing respiratory illnesses is challenging. That’s because respiratory tract infections can be caused by either viruses or bacteria, and standard diagnostic approaches have trouble pinpointing which particular pathogen is to blame. As a result, even though the vast majority of respiratory tract infections are viral, patients are often misdiagnosed and treated unnecessarily with antibiotics.
One of the best ways to help reduce this diagnostic “gap” is to improve the clinical understanding and utility of molecular diagnostics, such as PCR testing, says Christopher J. Michaud, PharmD, BCCCP, BCPS, Director of Clinical Treatment, Industry Lab Diagnostic Partners Owner and Principal, Pharmacotherapy Solutions, LLC.
In a 45-minute webinar titled Respiratory Season Considerations for the Laboratory: The Clinical Utility and Use Cases for a PCR-Based Testing Approach, Michaud reviews population data leading up to the 2023-2024 winter “tripledemic,” the seasonal peak of COVID-19, respiratory syncytial virus (RSV) and influenza cases, and provides an overview of current diagnostic methodologies, ultimately focusing in on the dire consequences that arise when these methods fall short. For example, research has shown that unnecessary and inappropriate antibiotic prescribing can result in more severe and prolonged disease, increased health care costs, and antimicrobial resistance [2].
What new approaches are needed to improve how respiratory tract infections are diagnosed?
Michaud uses the second half of his presentation to address this question and outline potential solutions. The answer, he says, lies in improving the utility and understanding of molecular tests.
As Michaud points out, even though conventional sputum culture and point-of care immunoassay tests are popular and widely used, each can have significant drawbacks, especially for diagnosing outpatients with respiratory illness. Advanced PCR testing, by contrast, can quickly and accurately rule viral infections in or out. That means PCR testing can not only support provider diagnoses in outpatient settings, but also improve both patient outcomes and antibiotic stewardship—by ensuring each infection receives prompt, appropriate treatment (with antibiotics or antivirals, if needed).
While studies investigating the clinical utility of molecular diagnostics have shown significant patient benefits, most of that research has been conducted in inpatient environments and the field is poised to learn more from additional studies and meta analyses currently underway.
“There are hints that a viral plus bacterial test could have benefits to patient care and does influence prescriber practices,” Michaud says. “Again, most of this data is in the impatient space or in the emergency urgent care space because that’s where people are sickest. We’re still waiting for big data to come out of the outpatient space to really help define the role for PCR and especially multiplex PCR in those settings.”
Respiratory testing should be customized for the use case
Michaud also points out that PCR testing is not one-size-fits-all, and he uses an example of four hypothetical patients, each with symptoms of respiratory infection but different risk profiles, to illustrate how a PCR-based approach needs to be customized for optimal results.
“Respiratory diagnostics still center heavily around bacteria versus viral, and limiting unnecessary antibiotic use and all the negative consequences of that is really all of our jobs as providers, as patients, as payers, and as healthcare leaders,” Michaud concludes. “PCR testing I think still plays a complimentary role to respiratory diagnostics, and we’ll continue to wait for more evolving data to tell us how it affects patients clinically and financially to be able to help shape the true place in therapy for these tests.”
To learn more about the impact of PCR testing on clinical outcomes and antimicrobial stewardship, watch the webinar titled Respiratory Season Considerations for the Laboratory: The Clinical Utility and Use Cases for a PCR-Based Testing Approach. The use of well-designed, clinically relevant bacterial and viral panels for respiratory tract infections can improve diagnosis, enhance outcomes, and help limit unnecessary and inappropriate antibiotic prescribing.
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