Diagnosis of IBS
Everyone has a bout of abdominal pain and diarrhea or constipation now and then. That’s not unusual. It is unusual when the symptoms persist or keep coming back. When that happens, it’s time to see a doctor to find out why.
Making the Diagnosis
There are no tests that identify IBS (like standard blood tests, x-rays, scopes, or scans). Instead, IBS is diagnosed based on defined patterns of signs and symptoms.
A doctor will start by asking about symptoms and health history, and then do a physical exam and limited tests. 
Learn More about Testing in IBS
Warning Signs and Symptoms
Warning signs and symptoms are not typical of IBS. The doctor may want to run extra tests if you have any of the following:
- anemia and other abnormal blood tests,
- blood in the stool,
- unexplained weight loss,
- fever, or
- a family history of inflammatory bowel disease or other diseases of the colon
IBS Signs and Symptoms
The typical signs and symptoms of IBS are...
- pain or discomfort in the belly (abdomen),
- that happens several days or more per month over at least the last 3 months, and
- is related to changes in the way your bowel moves, meaning the pain/discomfort…
- gets better after a bowel movement, and/or
- happens when bowel movements become more often or less often, and/or
- when stools are getting harder or softer
Other Common Digestive Symptoms
The signs and symptoms listed above are distinguishing features of IBS. But other symptoms are also often felt by persons with IBS - digestive symptoms such as...
- Bloating
- Heartburn
- Early feeling of fullness
- Nausea
- Upper belly discomfort or pain that comes and goes (dyspepsia)
- Feelings of urgency (the need to find a restroom fast)
- Passage of mucus in the stool
- Feeling of "incomplete" bowel emptying
Some Symptoms Aren't Digestive
And symptoms that don't seem related to the digestive tract such as...
- Fatigue
- Muscle pain
- Sleep disturbances
- Sexual dysfunction
- Low back pain
- Headache
The Bottom Line
A doctor familiar with IBS will likely be able to make a diagnosis based on your symptoms, a history and physical exam, and few basic tests. Once you have a diagnosis you can start finding ways to best manage and treat your IBS.
Discover more about IBS:
- Current Approach to Diagnosis of IBS. Go »
- IBS in Men: A Different Disease? Go »
- Is it IBS or Something Else? Go »
- A complete listing of articles on IBS in our Learning Center Library. Go » (All articles in our online Library are Free to Members. Join now.)
The Rome III Diagnostic Criteria*
(a system for diagnosing functional gastrointestinal disorders based on symptoms) for IBS is as follows:
Recurrent abdominal pain or discomfort** at least 3 days per month in the last 3 months associated with 2 or more of the following:
- Improvement with defecation
- Onset associated with a change in frequency of stool
- Onset associated with a change in form (appearance) of stool
* Criteria fulfilled for the last 3 months with symptom onset at least 6 months prior to diagnosis.
** "Discomfort" means an uncomfortable sensation not described as pain.