Diagnostic Criteria for Irritable Bowel Syndrome

Introduction to IBS Diagnosis

The American Gastroenterological Association recommends that symptoms must be present for at least 6 months to distinguish IBS from transient conditions such as infections or other self-limiting disorders 2
The Rome III criteria specifically require that criteria be fulfilled for the past 3 months with symptom onset at least 6 months before diagnosis, as established by the American College of Gastroenterology 3, 2

Celiac disease should be excluded with serologic testing, according to the American College of Gastroenterology 6
Inflammatory bowel disease should be considered, particularly if other alarm features are present, as recommended by the Crohn's and Colitis Foundation 6
Infectious causes should be considered, especially if there's travel history or endemic area exposure, as suggested by the Centers for Disease Control and Prevention 6

A complete blood count, C-reactive protein or ESR, celiac serology, and fecal calprotectin should be obtained, as recommended by the American College of Gastroenterology 6
Screening for alarm features, including age >50 years, documented weight loss, nocturnal symptoms, rectal bleeding, anemia, fever, or family history of colon cancer or IBD, is necessary, according to the American Gastroenterological Association 1, 4, 6
Stool examination for ova and parasites should be considered if travel history or persistent diarrhea is present, as suggested by the Centers for Disease Control and Prevention 6

The American College of Gastroenterology recommends that IBS should not be diagnosed if the duration criterion is not met 2
Baseline investigations should be completed to exclude organic disease, as recommended by the American Gastroenterological Association 6
Reassessment in 3-6 months is necessary, and if symptoms persist without alarm features and investigations are normal, then IBS diagnosis becomes appropriate, according to the Rome III criteria 2, 6