Molecular testing offers greater reliability and flexibility for GI pathogen analysis
The United States is witnessing its largest Cyclospora outbreak on record, with more than 4,000 cases and at least 300 hospitalizations confirmed by the Centers for Disease Control and Prevention as of late July. While cases linked to a specific source of iceberg lettuce have been found across nine states, the overall outbreak is much larger, as 45 states have reported recent cases.
Testing for the parasite that causes cyclosporiasis can be very challenging. Traditional clinical laboratory tests rely on stool samples, with technicians selecting small sections for microscopic analysis. Even for highly trained technicians, it is all too easy to miss the evidence of a parasite amid the larger sample. Unfortunately, negative results do not actually rule out an infection.
Molecular testing overcomes the limitations of traditional stool testing by detecting the genetic code of the pathogen, even when there is not enough evidence to identify by eye. Diasorin’s LIAISON PLEX® Gastrointestinal Flex Assay was designed to give labs and clinicians as much flexibility as possible while covering all relevant targets for each clinical situation.
We caught up with Michelle Tabb, PhD., Chief Scientific Officer for the molecular division of Diasorin, to learn more about the ongoing Cyclospora outbreak, what it means for clinical laboratories, and how it highlights broader trends in gastrointestinal testing.
Check-out the highlights below or watch the full video interview.
What can laboratories learn from this foodborne parasitic outbreak?
Because reporting takes a few weeks to catch up, we should anticipate that the outbreak is actually larger than the current numbers show, Dr. Tabb says. This situation underscores the importance of detecting cases faster so patients can be treated quickly, and of using molecular tests to make sure that results are reliable.
What are the diagnostic challenges involved with ruling out a parasitic infection?
Traditional testing of stool samples can easily miss positive cases. It’s also a difficult test to scale, and in an outbreak situation, testing volume can easily overwhelm labs, Dr. Tabb explains. Molecular tests that include multiple parasites provide a more reliable level of detection with greater efficiency.
What are the biggest challenges in diagnosing patients with gastrointestinal symptoms today?
Bacterial, viral, and parasitic pathogens can all cause common symptoms, making it very difficult to home in on the real culprit. There’s also a time crunch; results must be generated quickly so patients can start on the right treatment as soon as possible. And while labs are dealing with increased testing volume in an outbreak situation, they also have to balance reimbursement considerations, Dr. Tabb says.
Why is diagnostic flexibility increasingly important in gastrointestinal testing?
There is no one-size-fits-all approach for GI testing, Dr. Tabb notes. Labs have to adjust for seasonal outbreaks — such as Cyclospora in the summer and norovirus in the winter — as well as patient demographics and history, such as recent travel. A full syndromic panel that might be appropriate for one patient is probably not appropriate for many other patients. Labs need a flexible testing solution that allows them to customize target selection based on the clinical situation.
What’s the rationale for moving away from using the same syndromic panel for all patients?
According to Dr. Tabb, clinical labs must be able to adjust their GI targets on a case-by-case basis. Diagnostic testing platforms must be able to answer the need for flexibility in the clinic.
What are the upcoming trends to watch in GI diagnostics?
It’s high time to rethink the use of large syndromic panels for GI testing, Dr. Tabb stresses. To meet the goals of antimicrobial stewardship and diagnostic stewardship initiatives, as well as to rein in healthcare costs, laboratories will be focusing more on platforms that enable greater control over the targets to be tested for each patient.
Learn more about the LIAISON PLEX® System for reliable diagnostic testing powered by Flex™ Testing.