Cleveland Clinic Journal of Medicine (CCJM)Which Patients with Presumed Acute Infectious Diarrhea in an Outpatient Setting Should Undergo Gastrointestinal Pathogen Panel Testing?

This article provides evidence-based guidance on appropriate use of multiplex PCR gastrointestinal pathogen panels in outpatient settings. The authors present criteria for testing based on clinical presentation and highlight the advantages of rapid multiplex testing over traditional diagnostic methods for specific patient populations.

Key Clinical Considerations

• Testing indications: Multiplex PCR testing is warranted for patients with fever, visible blood in stool, sepsis, severe abdominal pain, hospitalization, persistent diarrhea (≥7 days), advanced age, or immunocompromised status.
• Pathogen spectrum: FDA-approved multiplex panels can detect up to 22 enteropathogens (bacteria, viruses, parasites) with greater sensitivity and faster turnaround times (as little as 1 hour) compared to traditional culture methods.
• Immunocompromised patients: These individuals are at higher risk for severe outcomes, with common pathogens including C. difficile, Salmonella species, Cryptosporidium, and Cyclospora cayetanensis, which can cause prolonged illness in this population.
• Insurance considerations: Coverage may be limited to panels with fewer than 5 targets by some insurers, requiring clinicians to be aware of potential coverage limitations when ordering comprehensive testing.
• Confirmatory testing: For C. difficile detection, additional testing such as antigen testing for toxin is required, and bacterial culture may be needed for susceptibility testing and public health reporting of bacterial pathogens.

Clinical Practice Impact

• Multiplex PCR testing offers significant advantages in select patients, improving diagnostic yield while potentially reducing 30-day follow-up costs and hospitalization risk compared to traditional workups.
• When ordering these tests, clinicians should carefully consider clinical presentation, immunologic status, and insurance coverage.
• For most immunocompetent patients with mild, self-limiting diarrhea lasting less than 7 days, testing may be unnecessary as these cases typically resolve without specific intervention.

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