Test Summary
Gastrointestinal Pathogen Panel, Real-Time PCR
Test code: 38470
Clinical use
- Identify cause of infectious diarrhea
Clinical background
Infectious diarrhea is caused by various pathogens, including viruses, bacteria, and parasites. Most cases of infectious diarrhea are self-limiting and brief; therefore, etiological diagnosis is not necessary.1 However, in populations that are susceptible to severe infection, timely diagnosis may expedite recovery and prevent complications.2
The severity and duration of disease, as well as epidemiological features, can also inform the decision to pursue laboratory testing to identify the cause(s) in affected patients. Guidelines from the American College of Gastroenterology indicate that stool diagnostic testing can be considered in cases of moderate to severe watery diarrhea or dysentery, or when symptoms last >7 days.2
Traditional tests (eg, bacterial culture, microscopy, antigen testing) can be time-consuming and inconclusive in determining the cause(s) of infectious diarrhea.2,3 Nucleic acid amplification test (NAAT) provides faster results and is a more sensitive alternative to culture-based methods.4 Singleplex NAAT targets 1 pathogen and is useful when clinical suspicion of a certain causative pathogen is strong. In other scenarios, multiplex NAAT panels (ie, syndromic panels), which detect multiple pathogens in 1 test, reduce the time to diagnosis and may improve patient outcomes.2,5 These scenarios include etiological investigation in immunocompromised or hospitalized (<72 hours) individuals or when stool culture or singleplex NAAT have negative results.6
The Gastrointestinal Pathogen Panel, Real-Time PCR is a syndromic panel that simultaneously tests for some of the most common causes of infectious diarrhea in the United States, including 5 bacteria, 2 viruses, and 2 toxins (Table).7,8 This test panel may not be appropriate for immunocompetent individuals with uncomplicated infectious diarrhea or individuals hospitalized more than 72 hours. Testing for Clostridioides difficile (not included in this panel) should be considered in diarrhea associated with healthcare or antimicrobial use.1,6
Table. Pathogens Detected in the Gastrointestinal Pathogen Panel
Microbial source of panel component |
Pathogen detected |
||
Bacterial |
Campylobacter groupa |
Campylobacter coli |
|
|
Salmonella species |
Salmonella species |
|
|
Shigella species |
Shigella sonnei |
|
|
Vibrio group |
Vibrio cholera |
|
|
Yersinia enterocolitica |
Yersinia enterocolitica |
|
|
Shiga toxin 1 (stx1) |
Shiga toxin-producing Escherichia coli (STEC) |
|
|
Shiga toxin 2 (stx2) |
||
Viral |
Norovirus GI/GII |
Norovirus genogroup G1 and GIIb |
|
|
Rotavirus A |
Group A rotaviruses |
|
| a | A positive result for Campylobacter may indicate the presence of C insulaenigrae, a species found in marine mammals (seals and porpoises) that is closely related to C jejuni, C coli, and C lari.7 However, C insulaenigrae infections are extremely rare, only 2 cases have been confirmed (the latter found to be a different strain based on genotyping compared with the marine hosts).8 |
| b | Norovirus RNA, Qualitative Real-Time PCR (test code 19098) is orderable separately. |
Individuals suitable for testing
- Individuals with bloody stools (ie, dysenteric diarrhea); diarrhea that is moderate (illness forces change in activities) to severe (total disability); or diarrhea lasting >7 days2
- Individuals with suspected infectious diarrhea who are immunocompromised or hospitalized (<72 hours)6
- Individuals with suspected infectious diarrhea but stool culture or singleplex NAATs cannot identify causative pathogen6
Method
- Target amplification multiplex PCR–based and RT-PCR–based amplification of extracted nucleic acids
Interpretive information
A positive result (ie, “detected”) indicates the presence of the pathogens or toxins associated with infectious diarrhea (Table). However, such a result does not rule out co-infection with organisms that are not included in this panel.
A negative result (ie, “not detected”) indicates the absence of all pathogens and toxins targeted by this test. Because infectious diarrhea can be caused by pathogens not included in this panel, a negative result does not rule out an infectious cause.
Antacids, barium, bismuth, antibiotics, anti-malarial agents, antidiarrheal medication, and oily laxatives may cause false-negative results. Specimen collection should be delayed at least 2 weeks after administration of barium or antibiotics, and 5 to 10 days after administration of other compounds.
References
- Shane AL, Mody RK, Crump JA, et al. 2017 Infectious Diseases Society of America clinical practice guidelines for the diagnosis and management of infectious diarrhea. Clin Infect Dis. 2017;65(12):e45-e80. doi:10.1093/cid/cix669
- Riddle MS, DuPont HL, Connor BA. ACG Clinical Guideline: diagnosis, treatment, and prevention of acute diarrheal infections in adults. Am J Gastroenterol. 2016;111(5):602-622. doi:10.1038/ajg.2016.126
- Humphries RM, Linscott AJ. Practical guidance for clinical microbiology laboratories: diagnosis of bacterial gastroenteritis. Clin Microbiol Rev. 2015;28(1):3-31. doi:10.1128/cmr.00073-14
- Langley G, Besser J, Iwamoto M, et al. Effect of culture-independent diagnostic tests on future emerging infections program surveillance. Emerg Infect Dis. 2015;21(9):1582-1588. doi:10.3201/eid2109.150570
- Ramanan P, Bryson AL, Binnicker MJ, et al. Syndromic panel-based testing in clinical microbiology. Clin Microbiol Rev. 2018;31(1):e00024-17-e00024-17. doi:10.1128/cmr.00024-17
- Hata DJ, Powell EA, Starolis MW. Utility and recommendations for the use of multiplex molecular gastrointestinal pathogen panels. J Appl Lab Med. 2023;8(6):1148-1159. doi:10.1093/jalm/jfad009
- Foster G, Holmes B, Steigerwalt AG, et al. Campylobacter insulaenigrae sp. nov., isolated from marine mammals. Int J Syst Evol Microbiol. 2004;54(6):2369-2373. doi:10.1099/ijs.0.63147-0
- Kyotani M, Kenzaka T, Akita H, et al. Campylobacter insulaenigrae bacteremia with meningitis: a case report. BMC Infect Dis. 2021;21(1):633. doi:10.1186/s12879-021-06353-8
Content reviewed 6/2025
38470 - Gastrointestinal Pathogen Panel, Real-Time PCR
19098 - Norovirus RNA, Qualitative Real-Time PCR
Reference ranges are provided as general guidance only. To interpret test results use the reference range in the laboratory report.
The tests listed by specialty and category are a select group of tests offered. For a complete list of Quest Diagnostics tests, please adjust the filter options chosen, or refer to our Directory of Services.