METHODS OF DIAGNOSING IRRITABLE BOWEL SYNDROME

The invention provides a method for diagnosing irritable bowel syndrome (IBS) in a patient, the method comprising: (a) analysing the viral content of a gastrointestinal sample, such as a faecal sample, obtained from the patient; (b) calculating the gastrointestinal virome diversity of the patient on the basis of said analysing in (a); (c) comparing the gastrointestinal virome diversity of the patient calculated in (b) to the gastrointestinal virome diversity of a control population of one or more further patients; wherein if the gastrointestinal virome diversity of the patient is less than the gastrointestinal virome diversity of the control population, the patient is diagnosed as having IBS.