What You Need to Know About IBS Diagnosis

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If you have abdominal pain, bloating, and other symptoms, such as diarrhea or constipation, you may suspect that you have irritable bowel syndrome (IBS). IBS is a common disorder that affects up to 20% of people worldwide.

If you think you may have it, it’s important to see your doctor so you can know for sure. Getting a clear diagnosis is crucial to rule out more serious conditions and pave the way to finding a treatment plan that helps you feel better. 

You will likely work with your primary care doctor or a gastroenterologist to diagnose the cause of your symptoms. A gastroenterologist specializes in diagnosing and treating digestive system problems. Here are some things to know as you pursue a diagnosis for your abdominal pain.

Track and Communicate Your Symptoms

Diagnosing IBS is largely based on your symptoms. Your doctor will rely on you to provide details about how you feel and what you’re experiencing. To clearly understand and communicate your symptoms, write them down in a daily diary. Track your diet, bowel habits, stress levels, and when symptoms come and go. Women should also note their menstrual cycles. Try to be as thorough and detailed as possible when you are describing your symptoms. Often, the timing of your symptoms in relationship to your routine can be the key to identifying IBS. 

Use Symptoms for Diagnosis

Your doctor will use a set of specific symptom criteria—called the Rome Criteria—to help diagnose IBS. As part of this criteria, your doctor will want to know if you have abdominal pain. This is a key symptom of IBS, which many people describe as a cramping feeling. IBS-related abdominal pain improves after having a bowel movement. IBS abdominal pain also occurs with some kind of change in bowel habits. This could be a change in frequency—diarrhea or constipation—or a change in appearance of your stool.

Your symptom diary will be important when your doctor applies the Rome Criteria. Your doctor will be looking for patterns of abdominal pain. The criteria specify that abdominal pain should be present at least three days each month for the last three months. It’s also important to know that the criteria are only reliable when other digestive diseases are not present.

Rule Out Other Conditions

As part of the diagnostic process, your doctor will check for other digestive diseases or conditions. Your doctor will look for ‘red flag’ symptoms that may point to a condition other than IBS. These symptoms are not associated with IBS and require further investigation. They may include fever, blood in the stool, anemia, and unintentional weight loss. If you’re having any of these, note them in your symptom diary so you can clearly communicate the details. Keep your notes as accurate and as specific as possible. Don’t be timid in your descriptions—your doctor has heard it all before and is not easily embarrassed.

In addition to asking about your symptoms and health history, your doctor will give you a physical exam and may recommend testing to rule out other conditions. Blood tests look for markers—such as anemia or inflammation—that may indicate another problem. Stool tests can find blood in the stool or signs of infection. And a colonoscopy or sigmoidoscopy lets your doctor directly examine the lining of your large intestine. 

When test results are normal and your symptoms meet the Rome Criteria, IBS is likely the cause of your digestive problems. Keep in mind that normal does not mean that nothing is wrong or that you are imagining your symptoms. IBS is a functional disorder. This means that there is a problem with the way your system works, not how it looks on a test. Headaches are a common example of a functional disorder. They can be quite painful, but your doctor can’t see that on a test.

Work Together

As you can see, working closely with your doctor to get to the bottom of the problem is key to diagnosing IBS. Once you have a diagnosis, it’s important to continue a close working relationship with your doctor. Together, you can take steps to find relief. This will include identifying your triggers, making lifestyle changes, and possibly starting medication to control your symptoms. Continuing your symptom diary can help you and your doctor find what works for you and fine-tune your treatment.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2018 Sep 22

  1. Diagnosis of IBS. International Foundation for Functional Gastrointestinal Disorders. www.aboutibs.org/site/signs-symptoms/diagnosis.

  2. IBS: A Patient's Guide to Living With Irritable Bowel Syndrome. American Gastroenterological Association. www.gastro.org/patient-center/digestive-conditions/irritable-bowel-syndrome.

  3. Symptom Diary. International Foundation for Functional Gastrointestinal Disorders. www.aboutibs.org/site/signs-symptoms/symptom-diary.

  4. Testing in IBS. International Foundation for Functional Gastrointestinal Disorders. http://www.aboutibs.org/site/signs-symptoms/testing.

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