Diagnosis is important
Occasional symptoms like those described here may occur in almost anyone, without being diagnosed as IBS. IBS must be diagnosed by a doctor when these symptoms have occurred at least three times per month for six months or more. In this case, it is important to see a physician, to be sure that IBS, and not another condition, is the problem.
Source: http://digestive.niddk.nih.gov/ddiseases/pubs/ibs/. Accessed March 2015