Stool testing is not routinely necessary for most cases of uncomplicated traveler's diarrhea. However, there are specific circumstances where stool testing is recommended:
Indications for stool testing
- Severe or persistent symptoms: The International Society of Travel Medicine (ISTM) 2017 guidelines recommend obtaining microbiologic testing in returning travelers with severe or persistent symptoms or if empiric therapy has failed
- Symptoms lasting ≥ 14 days: The Infectious Diseases Society of America (IDSA) 2017 guidelines recommend testing for intestinal parasitic infections in patients with traveler's diarrhea lasting ≥ 14 days
- Antimicrobial treatment within the preceding 8–12 weeks: The IDSA 2017 guidelines recommend testing for C. difficile infection in patients with traveler's diarrhea who have been treated with antimicrobial agents within the preceding 8–12 weeks
- Rapid results are clinically important: The ISTM 2017 guidelines recommend obtaining molecular testing, aimed at a broad range of clinically relevant pathogens, when rapid results are clinically important or non-molecular tests have failed to establish a diagnosis
Stool testing methods
- Culture-independent stool testing: The IDSA 2017 guidelines suggest culture-independent methods of diagnosis, if available, as an adjunct to traditional methods to identify infectious causes of acute diarrhea
- Molecular techniques: The IDSA 2017 guidelines recommend recognizing that molecular techniques generally are more sensitive and less dependent than culture on the quality of the specimen. Fresh stool is preferred for identification of viral and protozoal agents and C. difficile toxin
In conclusion, while stool testing is not routinely necessary for most cases of uncomplicated traveler's diarrhea, it is recommended in specific circumstances such as severe or persistent symptoms, symptoms lasting ≥ 14 days, recent antimicrobial treatment, or when rapid results are clinically important. The choice of testing method may include culture-independent stool testing and molecular techniques.