IBD diagnosis

Working out if someone has IBD usually involves a number of steps. 

Usually, not all of the standard tests will be performed on the same day and most can be done on an outpatient basis.


The very first step in working out a diagnosis of IBD involves your doctor taking a very thorough and detailed history of your complaint. You will be asked many questions about your current troubles (abdominal pain, bowel habits etc).

 Your doctor will also ask about your general health (eg growth, energy level, school attendance) and about the health of your family (especially if anyone else in the family has bowel problems, such as IBD).

Physical examination

Your doctor will perform a complete physical examination. This involves inspecting your skin, mouth and belly, feeling your tummy, listening to your tummy and checking many other parts of your body. 

During any examination your doctor will not be trying to hurt you: if anything is painful for you, please let them know.


Blood and stool tests

The next step will include some blood and stool tests. The blood tests give the doctor some information about your overall health, as well as checking how your gut is functioning.

Blood tests will be done to measure several markers of inflammation: some of these names are the erythrocyte sedimentation rate (ESR) and the C-reactive protein (CRP) level. Other blood tests may be needed depending on how long you have been sick and your particular symptoms.

Commonly in children with Crohn's, there may be a low blood count, low iron, low albumin, high platelet count, high ESR and high CRP. Other people can have just one or two changes present. However, for some children, all these tests will be normal even when their IBD is active.

Stool sample will be requested to see if there are any infections (bad bugs) : sometimes bowel infections can look just like IBD. The lab will also be asked to examine the stool sample to look for signs of  bowel inflammation. 

Upper Gastrointestinal Endoscopy and Colonoscopy (Scope tests)

The next test you will need is usually the scope tests. These are very important to find out if someone does actually have IBD, to show the parts of the bowel involved and to work out if the IBD is Crohn's disease or ulcerative colitis.

The scope tests involve looking at your upper gut (called upper gastrointestinal endoscopy) and your lower bowel (called a colonoscopy). The scope is a long flexible tube with a bright light and a tiny camera on its tip that projects an image onto a screen.

In the upper gastrointestinal endoscopy, the tube is placed down your throat through the oesophagus (gullet), through the stomach and into the first part of the small bowel (called the duodenum). The colonoscopy involves examining the large bowel from your bottom up to the end of the small bowel (called the terminal ileum) by placing the scope into your bottom.

Your doctor will be able to work out the severity of the inflammation and the areas involved and can tell you or your parents just after the scope what it looks like. During the scope test, your doctor will take a number of small (few millimetres) samples (called biopsies) from the surface of the bowel wall by passing a small instrument through the scope.

These biopsies are later examined in great detail under a microscope. As the samples need to be carefully prepared, it usually takes a few days before these results are available. The biopsies are really important to work out whether or not someone has IBD and also are needed to help work out whether it is Crohn's disease or ulcerative colitis.

You will be asleep for the scope tests. This will involve an anaesthetic and means that you will not be in any pain or discomfort. You will need to have an empty stomach, which means not eating for at least 6 hours beforehand.

Also, so that the colonoscopy can be successful, the poo in your bowel needs to be washed out. This might be the most unpleasant part of the whole procedure for you.

It means drinking a special liquid (a powerful laxative) followed by a lot of clear fluids, starting usually at midday on the day before the scope tests. This part of the preparation is very important so that your bowel is clean, giving your doctor a proper view of the bowel wall.

The scope tests take around an hour and take place in the operating theatre. One of your parents can be with you when you are going off to sleep and can be with you again just after you wake up in the recovery ward. Usually, you will be in the hospital for most of a day, but not usually overnight.

Imaging studies of the small bowel

With the scope tests, your doctor can see the first and last parts of the small bowel but they cannot see the middle parts. You will have to have a different test to look at this part of the gut.

MRI ccan to look at parts of the bowel will likely be ordered at some stage during their care in IBD clinic. Magnetic Resonance Imaging (MRI) scan also involves lying still in a noisy large machine after drinking a liquid that helps to distend the small bowel on the pictures.

In very special circumstances, your doctors may suggest that you need to have a Pill Camera Test (or capsule endoscopy). This is a new type of test which involves a small capsule which travels through the bowel. It is able to take pictures, mainly in the small bowel, and transmit the pictures back to a recorder.

This type of test is being used more in people with suspected Crohn's disease and may become more common in the near future.

Last updated Friday 15th December 2023