How is IBS Diagnosed?

Is Irritable Bowel Syndrome a Disease?


Relief Report 019: How do I know if I have IBS?

Relief Report 019: How Do I Know if I Have Irritable Bowel Syndrome (IBS)?To get clear on your Triggers, download our checklist here

Posted by Stephanie Clairmont, RD on Wednesday, November 29, 2017

What is Irritable Bowel Syndrome?

Irritable Bowel Syndrome, or IBS, is a chronic condition characterized by a wide range of digestive symptoms like abdominal pain, bloating, gas, diarrhea and constipation. IBS is very common and affects about 10% of the population worldwide.

If you experience these symptoms frequently and they are interfering with your life then it’s worth talking to your doctor about IBS. If you are having these symptoms at night (they are waking you up) or you have blood in your stool, this is not typical with IBS and may be a sign that something else is going on, so it’s best to get checked out by your doctor. The main thing I want you to know here is that if you think you may have IBS, you need to get diagnosed by your doctor before making any changes to your diet.

Unlike Inflammatory Bowel Disease (IBD), IBS does not involve inflammation of the digestive tract. We aren’t going to get into IBD in this post, we will save that topic for another time 😉


Is IBS a Disease?

The short answer to this question is, not really. A disease usually refers to a state of health where the underlying cause is known. Since we don’t know what causes IBS, and as the name suggests, IBS is better described as a syndrome which refers to a grouping of symptoms that occurs together.

IBS is classified as a functional gastrointestinal disorder (FGID). But what exactly does that mean?

A FGID refers to a syndrome (group of symptoms that occur together) and is strongly linked to patients’ interpretation and reporting of the illness experience. FGIDs are often characterized by  abnormal motility (how fast or slow your digestive process works), but this is not a defining characteristic of a FGID. In addition to motility problems, FGIDs can also be related to increased sensitivity to abdominal pain, or a brain-gut dysfunction. This classification based on symptoms means that the information you provide your doctor is very important in helping them come to a diagnosis.  

The History of IBS Diagnosis

The process of identifying and classifying FGIDs began in the late 1980s, when a group of international experts were recruited by an Italian professor in preparation for the International Gastroenterology meeting in Rome in 1988. The meeting was called so these experts could try to better understand gastrointestinal disorders that were not very well known at the time, and to develop diagnostic guidelines for irritable bowel syndrome. This was the start of the Rome process.

In addition to IBS, these experts developed diagnostic criteria for 21 FGIDs which allowed scientists around the world to conduct research and try to better understand the cause of these disorders. These diagnostic criteria made it possible for research to be conducted, because there was now a clear definition of what IBS was and what is was not. The diagnostic criteria also helped to legitimize the struggles of patients having these symptoms.

Almost 30 years after this first meeting, we are now at the fourth version of these guidelines and diagnostic criteria for FGIDs. As more and more research is published and we learn new things about what causes IBS and how to treat it, these guidelines and diagnostic criteria need to be updated. The Rome IV classification and criteria were published in May 2016.


Rome IV Criteria for Diagnosing IBS

Here are the most recent diagnostic criteria doctors should be using to diagnose IBS.

Recurrent abdominal pain, on average, at least 1 day/week in the last 3 months, associated with two or more of the following criteria:

  • Related to defecation
  • Associated with a change in frequency of stool
  • Associated with a change in form (appearance) of stool

This means that if you experience abdominal pain at least once per week, and have experienced this pain every week for at least 3 months, you meet the first criteria for an IBS diagnosis. But meeting this criteria alone is not enough. You must also meet at least two of the other criteria. If you only meet one of the additional criteria, this is not enough for your doctor to diagnose you with IBS.

You must meet these criteria for at least the last 3 months with the onset of your symptoms beginning at least 6 months before for an IBS diagnosis to be made.

Because these diagnostic criteria exist, this means IBS shouldn’t be a diagnosis of exclusion, meaning your doctor shouldn’t just suggest that you might have IBS after they have run some tests and rule out other reasons for your symptoms.

If you meet the diagnostic criteria for IBS, your doctor may still test you for other related digestive conditions since many of them all share the same symptoms. Ruling out other conditions is important because it will determine the most effective and safest course of treatment for you.

So, if you’ve been suffering from abdominal pain, constipation, or diarrhea for a long time now, I really strongly encourage you to take that first step and visit your doctor. I know it can be scary, but it really is the first step to get you feeling better! If you suffer from these symptoms, know that you are not alone and there is help for you. This doesn’t have to be your new normal.

Identify Your Triggers

Once you have a diagnosis from your doctor, then we can work on identifying your food triggers to help minimize your symptoms and get you back to living your life and doing the things you love! All without the constant worry of where the nearest bathroom is or when your symptoms might show up! It may seem like a lifetime ago that this was even possible for you, but I know we can get you back to a good place, my friend. What you need is a step-by-step plan that works. No jumping from diet to diet, eliminating food after food trying to find relief! The key is identifying your triggers. No two people will have the same ones, that’s why those one-size-fits-all diets will never work for you. You need a customized approach.

I also want to let you know that is you don’t meet the criteria for IBS but you are still struggling with symptoms, that doesn’t mean that what you’re going through isn’t real and can’t be fixed. Feeling comfortable, happy, and healthy in your own skin is something everyone deserves, and it would be my pleasure to help you get there.

The first step if you’re looking to improve irritable bowel syndrome (IBS) or another digestive disorder or disease, is to understand more about the Low FODMAP diet and if it can help. Download my free eBook to help you better understand this diet and get started implementing simple steps to get rid of symptoms like gas, bloating, pain, diarrhea or constipation related to IBS. Click here to get a copy emailed to you right away.

Wishing you much love & wellness,






Schmulson, M. J., & Drossman, D. A. (2017). What Is New in Rome IV. Journal of Neurogastroenterology and Motility, 23(2), 151–163.


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