New Therapies in Irritable Bowel Syndrome: What Works and When

Orla Craig


Curr Opin Gastroenterol. 2018;34(1):50-56. 

In This Article

Diagnosis and Subtyping

There is no valid biomarker for IBS, therefore, symptom-based diagnostic criteria such as the Rome criteria are used to standardize the diagnosis of all the functional gastrointestinal disorders including IBS. The most recent iteration of the Rome criteria, Rome IV was published in 2016. It defined IBS as recurrent abdominal pain on average, at least 1 day per week in the last 3 months with two or more of the following: related to defecation; associated with a change in the frequency of stool and associated with a change in the form (appearance) of stool. These criteria must have been fulfilled for the last 3 months with symptom onset at least 6 months before diagnosis.[1] Although necessary in the research setting, standardized diagnostic criteria such as this are somewhat less useful in the clinical setting. Where the Rome criteria are perhaps more helpful clinically is in the diagnosis of IBS subtypes. Pharmacotherapy in IBS is directed towards the predominant-bowel pattern, therefore, it is important to accurately subtype IBS. Rome IV[1] like Rome III[13] before it, recommended that IBS subtype is diagnosed on the basis of stool consistency as per the Bristol Stool Form Scale (BSFS).[14] Bowel habit subtypes should be based on BSFS on days with an abnormal bowel pattern.