From the Guidelines
Stool PCR testing in pediatric patients is primarily indicated for diagnosing gastrointestinal infections when a child presents with persistent or severe diarrhea, especially when accompanied by symptoms like fever, abdominal pain, or bloody stools, as recommended by the 2017 Infectious Diseases Society of America clinical practice guidelines 1.
Indications for Stool PCR
The test should be considered when symptoms last longer than 7 days, in cases of suspected bacterial pathogens like Salmonella, Shigella, Campylobacter, or E. coli, or when there's concern for parasitic infections such as Giardia or Cryptosporidium.
- Stool PCR is particularly valuable in immunocompromised children, those with recent antibiotic exposure, during outbreak investigations, or when conventional stool cultures have been negative despite ongoing symptoms.
- The test offers advantages over traditional culture methods, including higher sensitivity, faster results (often within 24 hours), and the ability to detect multiple pathogens simultaneously.
- However, it should be used judiciously as it may detect colonizing organisms that aren't causing disease, and results must be interpreted in the clinical context of the patient's presentation.
Special Considerations
For children under 2 years of age, testing for C. difficile is not recommended unless there are prolonged or worsening diarrhea symptoms, and other infectious or noninfectious causes have been excluded 1.
- In children 2 years of age and older, testing for C. difficile is recommended for prolonged or worsening diarrhea, while excluding other infectious or noninfectious causes first.
- Repeated testing for C. difficile during the same episode of diarrhea (within 7 days) is unnecessary 1.
Clinical Context
The clinical context of the patient's presentation is crucial in interpreting the results of stool PCR testing, as recommended by the 2018 clinical practice guidelines for Clostridium difficile infection in adults and children 1.
- The guidelines emphasize the importance of considering the patient's symptoms, medical history, and epidemiologic risk factors when interpreting the results of stool PCR testing.
- The test should be used in conjunction with clinical judgment and other diagnostic tools to guide treatment decisions and improve patient outcomes.
From the Research
Indications for Stool PCR in Pediatric Patients
The indications for stool PCR in pediatric patients can be summarized as follows:
- Diagnosis of acute gastroenteritis caused by various pathogens, including bacteria, viruses, and parasites 2, 3, 4
- Detection of gastrointestinal pathogens in stool samples, particularly in cases where stool culture and microscopy are negative or inconclusive 2, 3, 4
- Identification of specific pathogens, such as enteropathogenic Escherichia coli, Clostridium difficile, and norovirus, which can guide antimicrobial therapy 2, 3, 4
- Evaluation of pediatric patients with chronic diarrhea or inflammatory bowel disease, where stool PCR can help distinguish between infectious and non-infectious causes 5
- Detection of Helicobacter pylori infection in children, using stool-PCR as a non-invasive diagnostic tool 6
Key Points to Consider
- Stool PCR has higher sensitivity than stool microscopy, stool culture, and stool antigen tests for detecting gastrointestinal pathogens 2
- However, stool PCR results should be interpreted with caution and in conjunction with clinical findings and other diagnostic tests to determine the pathogenicity of the detected agent 2, 5
- The use of stool PCR can impact medical management, particularly in terms of antibiotic prescription and hospitalization decisions 4