How is IBS Diagnosed?

By Jason Demant

How IBS is diagnosed is an important topic. If you have discomfort, pain, bloating, diarrhoea, or constipation, you may be concerned that your symptoms are Irritable bowel syndrome (IBS). In this article, I will share with you five important questions to ask yourself. These are questions which, hopefully, your doctor will ask you in order to decide if you have IBS or another condition.


How is IBS Diagnosed


The Rome criteria, used to diagnose IBS, asks a doctor to see if a patient is showing any reoccurring symptoms, in particular pain or changed bowel habits, for six or more months. It’s important that the pain is connected to bowel movements. Meaning, that the pain may be relieved by having a bowel movement. Your doctor will wish to know about changes related to bowel movements themselves. Have your bowel movements changed in frequency or consistency.

IBS is diagnosed by looking at how frequently you experience certain symptoms:

  • Common IBS symptoms will include:
  • Gas and bloating
  • Abdominal pain
  • Possible weight loss
  • Blood in stool
  • An increased feeling of urgency to defecate
  • If pain is relieved after defecation or
  • A feeling of incomplete evacuation

There are two main irritable bowel syndrome (IBS) diagnoses

The two main types of irritable bowel syndrome (IBS) are IBS-C and IBS-D.

IBS-C is irritable bowel syndrome with constipation, or when constipation is the predominant symptom. In other words, your bowel habits are fewer or you experience difficulty defecating.

IBS-D is irritable bowel syndrome with diarrhoea. This is where IBS results in uncontrollable bowel movements.

There’s also a classification of IBS-M which refers to irritable bowel syndrome mixed. This is when someone experiences a mix of constipation and diarrhoea.

There is also IBS-U, which means unclassified IBS.

How IBS is diagnosed verses IBD

It’s extremely important to differentiate between IBS and IBD. IBS, of course, stands for irritable bowel syndrome. IBS is mainly to do with pain or having diarrhoea or constipation. The symptoms are pretty much centred around the colon.

However, IBD stands for inflammatory bowel disease. IBD refers to a group of digestive diseases that can cause inflammation, ulcers or lesions. Examples are ulcerative colitis and Crohn’s . 

IBD is more serious and will disrupt daily life more than IBS. IBD, as well, may require medication and in some cases surgery. It is important that your symptoms are investigated fully by your doctor. Always be honest about what you are experiencing and explain symptoms fully.

Watch a short video from UCLA Health about how IBS is diagnosed

How will your doctor diagnose IBS?

There are a whole host of different ways that your doctor will use to diagnose your IBS. IBS is often diagnosed by way of exclusion. This means that tests are carried out to exclude other, more serious, diseases or conditions. Since other causes are ruled out, the conclusion is that IBS is the cause of the symptoms.

Commonly your doctor will perform a diagnosis using many of the following:

  • Medical history
  • Family history
  • Colonoscopy
  • Sigmoidoscopy
  • Upper endoscopy
  • Stool tests
  • Blood tests
  • X-rays
  • CT scans
  • SIBO breath test
  • Celiac disease test
  • Physical examination



There may be also be tests to see whether you are intolerant of different foods and that intolerance is the cause of your changes in bowel habit. For food intolerance tests, a dietitian may be consulted.

 It is important to remember that there isn’t necessarily one unique test that will confirm 100% whether you definitely do or do not have IBS. That’s why your doctor will come up with a diagnosis using their experience and intuition, together with the results of all of these tests. That’s also why it’s so important to go to a gastroenterologist that you trust and you feel has the requisite expertise.


How is IBS Diagnosed NHS


How to prepare for your doctor’s appointment to diagnose IBS

If you are going to see if you have a diagnosis of IBS, first of all, it’s very important to feel calm and relaxed about the process. Your doctor is an expert and is used to seeing people with IBS on a daily basis. In fact, it is estimated that approximately 40% of patients seeing gastroenterologists are going with IBS symptoms.

If you do not have one already, it’s useful to have a clear understanding of your medical history. You might wish to ensure that you have any paperwork related to any allergy tests or intolerances to food. It is also very useful to know your family history about digestive issues, food intolerances, IBS, IBD or similar conditions.

If you have a doctor who is holistically minded, they may ask you also about stresses and strains in your life. Often IBS can be exacerbated by stress or traumatic events. So be prepared that they may ask you about this. Your doctor may also ask you to keep a food diary or a diary of bowel movements.

If you have any questions about how IBS is diagnosed, note these down before you go. This will mean you won’t get flustered or forget any important details you wish to raise during the consultation.

Be prepared that your doctor or gastroenterologist wish to help you by changing your food habits or diet, or may refer you to a dietitian.

How is IBS diagnosed? Here are five important questions your doctor may ask

Often IBS symptoms can appear to be very similar to other serious conditions, for example cancer of the colon or Crohn’s . It is therefore so important to get to the correct diagnosis. Often IBS is diagnosed by way of exclusion, by excluding other, more serious, conditions.

As mentioned, using the Rome criteria and of course their intuition and experience, a gastroenterologist will make a diagnosis. The Rome criteria looks at any important and alarming features of pain or bowel habits, that, taken together, point to an IBS diagnosis, especially when no other factors pointing to another condition.  

Here are five questions to consider. Your doctor may ask you these and more when determining how or whether you have a diagnosis of IBS.

Question one. How is your stool?

It may be shocking to ask people what their poo is like. It may sound light-hearted or even a little crude or childish to discuss your toilet habits. However, I’m sure that if you’ve been to a number of gastroenterologists or doctors about your IBS symptoms, you will already be used to people asking you how often you go to the loo and what sort of poo you do.

It is also a very broad question, including asking whether your stools are watery or loose, hard or soft? You will be asked if it is difficult to go to the toilet. When you do go, do you have to wait for a long time?

It’s really important to consider, as well, if you feel that you have completely evacuated the entire stool upon visiting the toilet. Alternatively does it often feel like you have had an incomplete bowel movement? Very soon you will get used to discussing this private area of life with medical professionals.

In the case of diarrhoea, it could be possible that there are other factors causing watery stools. Indeed constipation may also be an IBS symptom, but of course, constipation may also be due to other factors.

Question two. Do you experience any bloating or pain?

It is very common for people with IBS to have abdominal pain or bloating. This may be relieved by a bowel movement. Pain or bloating (distension), if it gets better upon going to the bathroom could be a sign of irritable bowel syndrome. You will also be asked about frequency of pain and how that pain feels and its location in the body and if discomfort increases or decreases with bowel movements.

Question three. Can you eat all food and do you feel full really quickly?

An important question often asked is about how satisfied and how quickly you feel satisfied after eating even a small meal. Often people who feel satisfied very quickly may have IBS, if other symptoms are present. If you feel satisfied quickly, that may be a signal that there is something to be looked at in your digestive system. If you frequently cannot finish a regular sized meal, it’s important to look at why that is. Hopefully your doctor will look into all possibilities, but certainly IBS is one of them.

Question four. Do you ever find blood in your stool?

If you ever find dark or black blood, that bleeding would be something to investigate. Black or bloody stool could be bleeding anywhere in your digestive system. If however, you also have discomfort and diarrhoea, it could be that it’s not IBS at all. This is a red flag and it is very important that your doctor performs other investigations, such as an endoscopy or colonoscopy.

If you’re having blood in your stool, ensure that this is looked into thoroughly and properly.

Question five. Do you frequently wake up at night needing to run to the toilet?

It’s true that IBS will itself sleep when the person sleeps. In other words, if you have an interrupted sleep due to constipation or diarrhoea, it may not be IBS causing these night time toilet visits. It may be something else and therefore may be a red flag, indicating that further investigation is required.

If you are experiencing diarrhoea on a daily basis, but it goes away when you go to sleep at night, that could be IBS. That is especially relevant if there is no weight loss, anaemia or other symptoms of worry.

If you are experiencing symptoms at night, that is certainly something to discuss with your gastroenterologist. That is particularly important if you have other concerns, such as other pains, weight loss, or have any hardness in your tummy, belly, or other areas.


How is IBS Diagnosed IBD


Do not ignore symptoms whether old or young. As we get older, symptoms that you may have previously dismissed as innocent, should certainly not be ignored. If you are over 50 years old, it’s extremely important that you ensure that all symptoms are thoroughly investigated.

Get your doctor to thoroughly check your IBS symptoms. These can include the colour of your stool, frequency of bowel movements, pains and changed eating habits.

It may be important also to see your doctor if you have any symptoms following travel to an area of if the world where any particular diseases or illnesses are prevalent.

Consider the questions above. Use them as a guide to prepare before seeing your doctor or gastroenterologist. It is useful to consider how an IBS diagnosis could be made and which signs will be looked for. If you are concerned about any symptoms, you must, first of all, go and see your GP or doctor.

I help people with IBS using hypnotherapy. I use ‘gut directed hypnotherapy’ to help people calm and relax their digestive system and deal better with IBS pain.

If you’d like to find out more about IBS and my sessions, please get in touch today.

Disclaimer: This article is for information purposes only and should not be treated as professional medical advice. Always consult a trained medical professional about any symptoms you experience or about taking or stopping taking both prescription and over the counter medications.

author avatar
Jason Demant Clinical Hypnotherapist
London hypnotherapist. Seeing clients in King's Cross and online. Diploma in clinical hypnotherapy, counselling and Neuro-linguistic programming (NLP) from Life Matters Training College, based on Harley Street, London. Fully insured and a validated practitioner of the General Hypnotherapy Standards Council and member of the General Hypnotherapy Register.