For many years, irritable bowel syndrome (IBS) has been a diagnosis of exclusion. Because there is no single reliable diagnostic test for IBS, patients with gastrointestinal symptoms would often have a whole series of tests and procedures to rule out other illnesses or conditions; if no medical explanation for the symptoms was found, the patient would be sent home with a diagnosis of IBS. This is still common practice in the clinical setting, and it makes sense to a point. Naturally, your doctor wants to make sure he or she does not miss another treatable diagnosis, particularly if alarm symptoms are present.
In the absence of alarm symptoms, and depending on your age, your doctor might be able to diagnose IBS based on your medical history and some basic blood work, without ordering further tests. This is a growing trend, based on the latest practice guidelines for physicians. At a minimum, it is good medical practice to screen patients with gastrointestinal symptoms for celiac disease, a relatively common disorder that can present with symptoms similar to IBS.
It is important not to diagnose yourself with IBS. Start with your primary care provider (PCP) to discuss your symptoms, diagnosis and treatment. If necessary, your PCP will refer you to a gastroenterologist. Women should also be evaluated to make sure abdominal symptoms are not related to gynecological problems. See your dietitian to discuss nutrition therapy for your condition.