Diagnostic Work-up

There is no specific laboratory or imaging test to diagnose irritable bowel syndrome. Currently the diagnosis of IBS relies on meeting Rome II inclusion criteria and excluding other illnesses based on history, physical exam, and laboratory testing.

Diagnostic Work-up Rome II Criteria for Diagnosis of Irritable Bowel Syndrome (2006) – Recurrent abdominal pain or discomfort at least 3 days per month in the last 3 months associated with 2 or more of the following: Improvement/relief with defecation Onset associated with a change in frequency of stool Onset associated with a change in form (appearance) of stool

Diagnostic Work-up Symptoms not typical of IBS: – New onset after age 50 – Weight loss – Rectal bleeding – Fever – Nocturnal diarrhea – Diarrhea that is persistent after a 48-h fast

Diagnostic Work-up Lab studies may include the following: – CBC count with differential to screen for anemia, inflammation, and infection – Erythrocyte sedimentation rate – Stool Exam

Diagnostic Work-up The following selected studies are directed by history: – Breath testing: Screen for lactose intolerance. – Thyroid function tests: Screen for hyperthyroidism or hypothyroidism. – Serologies or small bowel biopsy for celiac disease: Consider, especially in diarrhea- predominant IBS.

Diagnostic Work-up Gallbladder ultrasonography: Consider this test if the patient has recurrent dyspepsia or characteristic postprandial pain. Double-contrast barium enema: Screen for neoplasm and inflammation.

Diagnostic Work-up Colonoscopy - Indicated for patients with warning signs, such as bleeding; anemia; chronic diarrhea; older age; history of colon polyps; cancer in the patient or first-degree relatives; or constitutional symptoms, such as weight loss or anorexia.