IBS-U, or Irritable Bowel Syndrome Unsubtyped, is a classification of IBS where bowel habits don't fit neatly into the other IBS subtypes (IBS-C or IBS-D).
In more detail, IBS-U is defined as:
- Less than 25% of stools are hard or lumpy.
- Less than 25% of stools are loose or watery.
This means individuals with IBS-U experience a mix of normal bowel movements, constipation, and diarrhea, but neither constipation nor diarrhea predominates enough to classify them as IBS-C (constipation-predominant) or IBS-D (diarrhea-predominant). Their symptoms are less consistent and predictable.
In essence, IBS-U is the "catch-all" category for IBS patients who don't fit the Rome IV criteria for IBS-C, IBS-D, or IBS-M (mixed).
