What are the diagnostic criteria for Irritable Bowel Syndrome (IBS)?

From the Guidelines

The diagnosis of Irritable Bowel Syndrome (IBS) should be based on the Rome IV criteria, which require recurrent abdominal pain at least 1 day per week in the last 3 months, associated with two or more of the following: related to defecation, associated with a change in frequency of stool, or associated with a change in stool form, as outlined in the British Society of Gastroenterology guidelines 1. To diagnose IBS, the following criteria should be met:

• Recurrent abdominal pain, on average, at least 1 day per week in the last 3 months
• Associated with two or more of the following:
  • Related to defecation
  • Associated with a change in frequency of stool
  • Associated with a change in stool form
• Criteria fulfilled for the last 3 months with symptom onset at least 6 months prior to diagnosis
• Stool patterns should be classified based on the Bristol stool form types, with IBS subtypes including:
  • IBS with predominant constipation (IBS-C)
  • IBS with predominant diarrhea (IBS-D)
  • IBS with mixed bowel habits (IBS-M)
  • IBS unclassified (IBS-U) It is essential to exclude other conditions that might cause similar symptoms, and clinicians should look for "red flag" symptoms that warrant further investigation, as recommended by the British Society of Gastroenterology guidelines 1. The diagnosis is clinical, and extensive testing should be avoided unless red flags are present, as stated in the guidelines 1. This symptom-based approach is reliable because IBS is a functional disorder without specific structural or biochemical abnormalities that can be identified through conventional testing, as supported by the guidelines 1.

From the FDA Drug Label

*Rome II Criteria: At least 12 weeks, which need not be consecutive, in the preceding 12 months of abdominal discomfort or pain that has two out of three features:

1. Relieved with defecation; and/or
2. Onset associated with a change in frequency of stool; and/or
3. Onset associated with a change in form (appearance) of stool Symptoms that Cumulatively Support the Diagnosis of Irritable Bowel Syndrome: – Abnormal stool frequency (for research purposes “abnormal” may be defined as greater than 3 bowel movements per day and less than 3 bowel movements per week); Abnormal stool form (lumpy/hard or loose/watery stool); Abnormal stool passage (straining, urgency, or feeling of incomplete evacuation); Passage of mucus; Bloating or feeling of abdominal distension.

*Rome III Criteria: Recurrent abdominal pain or discomfort (uncomfortable sensation not described as pain) at least 3 days/month in last 3 months associated with two or more of the following:

1. Improvement with defecation;
2. Onset associated with a change in frequency of stool;
3. Onset associated with a change in form (appearance) of stool

The IBS diagnostic criteria are defined by the Rome II and Rome III criteria, which include:

• Abdominal discomfort or pain with at least two of the following features:
  • Relieved with defecation
  • Onset associated with a change in frequency of stool
  • Onset associated with a change in form (appearance) of stool
• Symptoms that cumulatively support the diagnosis of IBS, including:
  • Abnormal stool frequency
  • Abnormal stool form
  • Abnormal stool passage
  • Passage of mucus
  • Bloating or feeling of abdominal distension These criteria are used to diagnose Irritable Bowel Syndrome (IBS), including IBS-D (Diarrhea-predominant) and other subtypes 2, 3.

From the Research

IBS Diagnostic Criteria

• The diagnosis of Irritable Bowel Syndrome (IBS) is based on symptom-based criteria, such as the Rome criteria for functional GI disorders 4.
• The Rome criteria, recently updated to Rome IV, are used to diagnose IBS and other functional GI disorders 4.
• IBS is characterized by disturbances in bowel habits and abdominal pain in the absence of known organic pathology 4.

Diagnostic Approaches

• A thorough medical history and physical examination are essential in diagnosing IBS 5.
• Diagnostic studies for food intolerances are not considered cost-effective or particularly helpful 5.
• Exclusion diets may be beneficial in some cases 5.
• A 2-week diary of food intake and gastrointestinal symptoms can be helpful in identifying patterns and triggers 5.

Treatment Options

• Treatment of IBS is symptom-driven and employs both pharmacologic and nonpharmacologic approaches 4.
• Pharmacological treatment options for IBS include loperamide, bile acid sequestrants, antispasmodics, tricyclic antidepressants, alosetron, eluxadoline, and rifaximin 6.
• Rifaximin and eluxadoline are two newly FDA-approved medications for the treatment of IBS-D 6.
• Nonpharmacologic approaches, such as dietary modifications, fiber supplements, and behavioral strategies, are also important in managing IBS symptoms 5, 7.