The Rome criteria are guidelines that doctors use to help diagnose irritable bowel syndrome (IBS). Healthcare professionals may also use tests to rule out other medical conditions.

According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDKD), about 12% of people in the United States have IBS. Women are also up to twice as likely to develop it than men. Furthermore, a person under 50 years old is more likely to develop IBS than someone who is over 50 years old.

The symptoms of IBS can be similar to other conditions and vary between people. The Rome criteria serve as a valuable set of guidelines to help healthcare professionals diagnose IBS.

This article discusses the Rome criteria and how they can help doctors diagnose different subtypes of IBS. It also explores IBS symptoms that a person may experience and when to consult a doctor.

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The Rome criteria are guidelines that doctors may use when diagnosing IBS. A multinational group of scientists and clinicians called the Rome Foundation derived the Rome criteria by consensus. These experts are specialists in gut-brain interaction disorders.

The first set of criteria, Rome I, appeared in publication in 1994. Since then, there have been several updates to the criteria, with the latest, Rome IV, appearing in 2016.

However, doctors may have difficulty diagnosing IBS, as symptoms may change over time and overlap with other disorders. Therefore, the Rome criteria are helpful for healthcare professionals and scientists researching IBS.

What are disorders of gut-brain interaction?

The Rome IV criteria define IBS as a disorder of gut-brain interaction (DGBI). DGBIs involve gastrointestinal symptoms relating to a combination of:

  • motility disturbances, which refers to abnormal nerve and muscle contractions that interfere with the typical movement of food through the digestive system
  • visceral hypersensitivity, which refers to a lower threshold of pain or discomfort
  • altered mucosal and immune function
  • altered gut microbiota
  • altered central nervous system processing

DGBIs include IBS and other gastrointestinal disorders, such as functional dyspepsia, abdominal pain syndrome, and some gallbladder disorders.

Rome IV defines IBS as recurrent abdominal pain on average, at least 1 day per week in the last 3 months. It has links to two or more of the following:

  • relating to defecation
  • a change in the frequency of stools
  • a change in the form, or appearance, of stools

Additionally, Rome IV states that a person should fulfill these criteria for the last 3 months with symptom onset at least 6 months before diagnosis.

IBS subtypes

Rome IV uses the Bristol stool chart, which classifies stools into seven different types according to their shape and texture. The scale ranges from type 1, which involves separate hard lumps that are difficult to pass, to type 7, which refers to watery diarrhea.

Rome IV outlines IBS subtypes according to the days a person has atypical bowel movements. The IBS subtypes that Rome IV defines are as follows:

  • IBS with predominant constipation (IBS-C): More than a quarter of atypical bowel movements are Bristol stool types 1 or 2, meaning hard or lumpy, and less than a quarter have stool types 6 or 7, meaning loose or watery. Alternatively, when a person reports that most of their abnormal bowel movements are constipated.
  • IBS with predominant diarrhea (IBS-D): More than a quarter of atypical bowel movements are Bristol stool types 6 or 7, and less than a quarter have stool types 1 or 2. Alternatively, when a person reports that most of their abnormal bowel movements are diarrhea.
  • IBS with mixed bowel habits (IBS-M): More than a quarter of atypical bowel movements are Bristol stool types 1 or 2, and more than a quarter have stool types 6 or 7. Alternatively, when a person reports that most of their abnormal bowel movements are both constipation and diarrhea.
  • IBS unclassified (IBS-U): A person cannot accurately categorize their bowel habits into any of the above three groups.

In addition to altered bowel habits and abdominal pain from the Rome criteria definitions, a person may also experience the following symptoms of IBS:

According to a 2016 systematic review and meta-analysis of studies from 1995 to 2014, around 54% of people with IBS also had fatigue.

Furthermore, 2021 research indicated that chronic stress and poor sleeping habits had associations with self-reported IBS.

If a person has frequent, atypical bowel movements and abdominal pain, they should consider speaking with a doctor. A healthcare professional will ask about an individual’s symptoms and may use the Rome criteria to confirm if it is IBS.

The NIDDKD advises that certain symptoms may indicate that someone has another health problem instead of IBS. These symptoms include:

A doctor may refer someone for a stool test, blood test, or colonoscopy to rule out conditions such as celiac disease or inflammatory bowel disease. They may also suggest a hydrogen breath test to determine if someone has small intestinal bacterial overgrowth or difficulty digesting certain carbohydrates.

Additionally, some people develop postinfectious IBS, which is more common in:

IBS may also develop following a parasitic infection, such as giardiasis, which may have similar symptoms to IBS.

The Rome IV criteria define IBS and its different subtypes. A doctor may refer to the Rome criteria when diagnosing the condition.

IBS may cause symptoms such as irregular bowel movements and abdominal pain. However, these symptoms can overlap with other gastrointestinal disorders.

A person should consider speaking with a doctor if they think they have IBS or are experiencing regular digestive issues. A doctor may be able to diagnose the issue or refer a person for further tests if necessary.