Make a symptom-based diagnosis of IBS-D with confidence1

Irritable bowel syndrome (IBS) affects approximately 12 million adults in the US, yet the condition remains undiagnosed in at least 75% of patients.2

Diagnosis is based on clinical history, symptoms, physical examination, limited diagnostic testing, and exclusion of alarm features.1 In fact, the American College of Gastroenterology does not recommend routine diagnostic testing in patients when symptom-based criteria are fulfilled and alarm features are not present.3*

*Additional testing recommendations were proposed in 2019 by the American Gastroenterological Association’s (AGA) Clinical Practice Guideline Committee and in 2020 by the American College of Gastroenterology's (ACG) Clinical Guideline for Management of Irritable Bowel Syndrome to help clinicians choose appropriate laboratory tests to exclude other diagnoses in the setting of suspected functional diarrhea or IBS-D.4

Diagnosis should include:

1. History based on Rome IV Criteria1
  • Abdominal pain at least 1 day per week for the past 3 months associated with 2 or more:
    • - defecation
    • - change in stool frequency
    • - change in stool form

With symptom onset at least 6 months prior to diagnosis1

2. Exclusion of alarm features1,5,6
  • Symptom onset after age 50
  • Severe or worsening symptoms
  • Unexplained weight loss
  • Nocturnal diarrhea
  • Rectal bleeding
  • Iron-deficiency anemia
  • Family history of: colon cancer, celiac disease, IBD
  • Fever
3. Physical exam and limited diagnostic testing1

Use the “25% Rule” to determine IBS-D subtype1

On days with at least one abnormal bowel movement1:

  • <25% of bowel movements with hard, lumpy stool (type 1 or 2 on the Bristol Stool Form Scale)
  • >25% of bowel movements with loose, watery stool (type 6 or 7 on the Bristol Stool Form Scale)

The Bristol Stool Form Scale has been shown to be a reliable surrogate marker for colonic transit.
Copyright Rome Foundation, Bristol Stool Form Scale developed by Dr. Ken Heaton, University of Bristol, UK

IBD = inflammatory bowel disease

IBS-D = irritable bowel syndrome with diarrhea


XIFAXAN® (rifaximin) 550 mg tablets are indicated for the reduction in risk of overt hepatic encephalopathy (HE) recurrence in adults and for the treatment of irritable bowel syndrome with diarrhea (IBS-D) in adults.

  • XIFAXAN is contraindicated in patients with a hypersensitivity to rifaximin, rifamycin antimicrobial agents, or any of the components in XIFAXAN. Hypersensitivity reactions have included exfoliative dermatitis, angioneurotic edema, and anaphylaxis.
  • Clostridium difficile-associated diarrhea (CDAD) has been reported with use of nearly all antibacterial agents, including XIFAXAN, and may range in severity from mild diarrhea to fatal colitis. If CDAD is suspected or confirmed, ongoing antibiotic use not directed against C. difficile may need to be discontinued.