Syndromic testing provides labs flexibility, maximizes equipment and personnel resources, and helps control costs while delivering high-quality results to clinicians.

By Arvind Kothandaraman

As we enter the winter season, we’ve seen respiratory syncytial virus (RSV) infections on the rise, especially in children. Scientists have also predicted a more severe flu season based on Australia’s 2022 flu data (in the Southern Hemisphere of the globe, this runs from approximately April to September). At the same time, COVID-19 remains a part of our daily lives and will likely continue to be a major cause of death in the United States and in many places around the world. The fact that symptoms presented by RSV and influenza overlap with those of COVID-19 makes it critical to detect and differentiate these infections so that necessary measures may be taken to treat them and prevent further transmissions.

In order to tackle the challenges of what some are calling a “tridemic,” syndromic testing allows clinical labs to simultaneously target multiple pathogens with fewer resources.

What Is Syndromic Testing?

Syndromic testing integrates multiplex molecular panels to test for a broad array of pathogens that may present with overlapping signs and symptoms. Several analytical methods may be used to conduct syndromic testing, though a predominant one is RT-PCR, which remains the gold standard in diagnostics, particularly for SARS-CoV-2 infection. This method allows for a wider range of acceptable sample types, better flexibility of workflow and higher sensitivity as well as specificity. 

The number of panels integrated in different syndromic assays may vary depending on variables such as platform, buffer system, etc. Syndromic tests are designed with carefully selected primers and probes, which label specific regions of a virus with unique fluorescent dyes to differentiate signals from one another. Ideally, these individual tests within the panel work in concert without compromising the accuracy of the targets.

In addition to simultaneous and qualitative detection and differentiation of SARS-CoV-2, influenza A, influenza B, and RSV, syndromic testing can be used to detect other specific pathogens such as diagnosing a bacterial infection, parasites, and fungi for relevant syndromes. In the future, there likely will be more syndromic testing for other conditions, including urinary tract infections, pharyngitis causing bacteria, and viruses.

What Are the Benefits of Syndromic Testing?

Convenience is a noteworthy benefit of concurrently detecting multiple pathogens at once. However, it has more downstream benefits than one might initially expect. Beyond the test itself, many more resources go into a clinical laboratory workflow including collection media, extraction kits and reagents. Reducing the amount of needed resources can significantly cut costs for a lab.

There are also human resources, which managers must plan and account for. When testing demand ramps up during a flu season (or worse, a pandemic), labs face significant financial and operational strain. Implementing syndromic testing to keep pace with fluctuating demand can help alleviate some of this stress.

The importance of time savings cannot be understated either. A relatively short turnaround time enabled by syndromic testing means individuals get their results sooner and can seek immediate treatments as needed. This information ensures these individuals isolate and help stop viruses from spreading further.

As mentioned earlier, PCR tests implemented by syndromic testing may use blood, saliva, mucus, or tissue samples, which allow for greater flexibility in lab workflow. PCR tests also tend to allow for greater sensitivity and specificity—both are vital components for detecting highly infectious diseases such as COVID-19 and influenzas. Certain qualified tests allow laboratories to scale their testing up or down as the workflow remains largely the same. With automation flexibility, assays can be coupled with modular, scalable extraction and liquid handling options suitable to process a broad range of samples each day based upon the lab’s requirements.

What Is the Outlook for Future Applications of Syndromic Testing?

 The emergence of novel viruses has triggered discussions around developing broader syndromic tests for use by clinical labs. We expect future additions to syndromic testing panels that will help expand coverage and identify viruses that are not routinely screened for by most clinical labs. As a result, more work will be necessary to improve the economics of testing for known and unknown pathogens and explore what can be done to pay for future developments in this area of diagnostics.

Advances in the development of syndromic tests may also contribute to ongoing pathogen surveillance, especially when applied in conjunction with other technologies. For example, next-generation sequencing (NGS) technology could guide syndromic test developers in adapting panels to target pathogens more precisely based on public health demands. As costs continue to decrease for NGS and more labs build expertise with this technology, syndromic testing could reach its full potential.

Also, when integrated with fully automated workflows, high-throughput syndromic testing will allow faster operations and superior efficiency due to standardization. Fully automated systems will enable labs to free up personnel for more sophisticated work where their expertise is needed, and its recognized high accuracy and throughput will help physicians make critical and time-sensitive clinical decisions.

It is clear that syndromic testing will play an important role in monitoring and managing infectious diseases in the future.

Arvind Kothandaraman is managing director, specialty diagnostics for PerkinElmer, Inc.