Clinical Research Directory

Inclusion Criteria: * \- Age 2 to 18 years * Chronic gastrointestinal symptoms of more than 4 weeks duration (chronic diarrhea, recurrent abdominal pain, rectal bleeding, unexplained weight loss, or failure to thrive) * Scheduled for upper gastrointestinal endoscopy and/or ileocolonoscopy with mucosal biopsy * Written informed consent from parents or legal guardians Exclusion Criteria: * Age below 2 years * Use of NSAIDs, systemic corticosteroids, or antibiotics within 4 weeks before stool sampling * Documented acute gastrointestinal infection, surgical gastrointestinal bleeding, or intestinal parasitic infestation * Previous gastrointestinal surgery, known malignancy, chronic liver disease, chronic kidney disease, or cystic fibrosis * Refusal of parents or legal guardians to participate * Failure to obtain an adequate stool sample