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Syndromic Testing

Q&A with the experts: Syndromic testing for infectious diseases

By QIAGEN Syndromic Testing

Our approach to the diagnosis and management of infectious diseases has shifted dramatically in the wake of the COVID-19 pandemic.

As SARS-CoV-2 approaches endemic status, it will become increasingly important to quickly distinguish COVID-19 from other influenza-like illnesses. As a result, there’s a growing need for rapid diagnostic tools that can detect and differentiate multiple pathogens at once. Multiplex PCR panel tests – widely known as syndromic testing – can do just that, and facilitate faster clinical decision making and infection control. But how is syndromic testing currently being used in the clinic and how will it impact diagnostics going forward?

We explored these topics in late 2021 during the QIAGEN Virtual Event: Syndromic Testing for Infectious Diseases. Three guest experts – Prof Dr med Stephan Gehring, Roy F. Chemaly, MD, MPH, FACP, FIDSA, CMQ and Susan A. Weaver, PhD, CLS – discussed their personal experiences using syndromic testing and addressed pressing questions about this diagnostic approach. Here, we’ve summarized their responses.

Read on to gain practical insight into the implementation and use of syndromic testing in the clinic. If you missed the virtual event, you can watch some of the recorded presentations on our webinar hub.

What are the benefits of transitioning from singleplex PCR tests to multiplex PCR panel tests (syndromic testing)?

Dr. Weaver mentioned that small and medium hospital labs experience daily pressure due to staffing shortages, limitations on staff expertise and space constraints. For example, clinical laboratory staff are often trained as generalists and don’t necessarily have the expertise to easily implement new molecular tools. However, Dr. Weaver has found that sample-to-answer syndromic testing platforms are simple enough to adopt that clinical laboratory staff can use them while continuing to work as generalists. In Dr. Weaver’s lab, syndromic testing has proven to be an extremely efficient solution for staffing issues and other lab constraints.

In Dr. Gehring’s experience, the syndromic approach has benefited his clinical practice in two main ways. First, it has expedited the time from hospitalization to diagnosis for his patients. Second, it has provided him with additional confidence that potential causative pathogens aren’t overlooked during the diagnostic process. He noted that being able to quickly assess several pathogens at one time is particularly important for diagnosing high-risk patient populations, such as immunocompromised patients.

Dr. Chemaly added that once SARS-CoV-2 becomes endemic, syndromic testing will play an important role in identifying co-infections in patients with respiratory illnesses going forward.

Could syndromic testing become the standard of care for infectious disease diagnostics in the near future? What are the opportunities and limitations here?

Dr. Gehring indicated that syndromic testing has already become the standard of care in his hospital. He noted that this diagnostic tool is replacing conventional approaches, like singleplex PCR, because it cuts down on time-to-diagnosis and provides fast, sensitive results.

Dr. Gehring suggested that, in some cases, syndromic testing can provide too much information. For example, he’s observed situations in which three or more pathogens were simultaneously detected in a patient sample and it was difficult to distinguish between a true infection and colonization. But the comprehensive information provided by this technique is also one of its major strengths, and can even challenge long-held clinical perceptions.

Dr. Chemaly noted that, from a patient management and infection control standpoint, it’s important to know what pathogens a patient may be carrying, so that isolation and therapy decisions can be tailored accordingly. Similarly, Dr. Weaver indicated that this information can be useful for epidemiological surveillance purposes.

What role does the clinician play in successfully implementing new diagnostic tools?

Dr. Chemaly indicated that two-way communication between the clinic and microbiology lab is necessary to successfully implement syndromic testing. It’s important for both parties understand the need for this approach and how it can change patient management decisions. Dr. Gehring echoed this sentiment, adding that close interactions with experts from the microbiology lab are required to help clinicians get the most value out of syndromic testing.

Dr. Weaver expressed her frustration with not being able to confirm a clinician’s working diagnosis for two days or more due to the long turnaround time required for traditional diagnostic methods. Syndromic testing allows her lab to stay in step, and in better communication, with clinicians.

What is the biggest obstacle in the implementation of new diagnostic tools?

Dr. Weaver indicated that the skill level of clinical laboratory staff can sometimes be a limiting factor, as the majority of laboratory staff are trained as generalists. This, combined with general staffing constraints, means there often isn’t time for additional staff training. She noted that education about these new molecular methods must also occur across many levels, from the patient, to laboratory administration, to the C-suite, to the clinician. These issues can be resolved with cross-training from public health and university labs, creating cross-functional partnerships and, at times, prioritizing training over productivity.

Which patient populations benefit the most from syndromic testing?

According to all three panelists, multiple high-risk patient populations can benefit from syndromic testing. For immunocompromised patients, including cancer patients, and those in critical care, syndromic testing is of high value and is used frequently in both Dr. Chemaly’s and Dr. Gehring’s hospitals. Dr. Chemaly highlighted that these patients can be susceptible to many different infections at any time. In his experience, using a multiplex approach for pathogen identification is important for these patients, as he’s been able to provide faster, better care.

In Dr. Weaver’s experience, patients in the mental health unit at her hospital have also benefited from syndromic testing, as they are not always able to accurately express how they’re feeling and what’s wrong with them.

Finally, Dr. Gehring noted that a rapid, accessible diagnostic tool like syndromic testing is of high value during an outbreak or pandemic situation, as the COVID-19 pandemic has demonstrated.

How will syndromic testing impact diagnostics going forward?

Dr. Gehring believes that rapid molecular tests represent an exciting future for diagnostics and are already changing clinical practice. He felt that the true value of these tests becomes apparent through their use, and he’s found that syndromic testing is used frequently in his hospital, which underlines its value for clinicians and clinical microbiologists. He again indicated that syndromic testing is quickly replacing assays that test for only a single pathogen, as they are more flexible during testing surges.