Diagnosis - Coeliac disease

Your GP will diagnose coeliac disease by giving you a blood test. They may refer you for a biopsy too.

You should not be tested for coeliac disease unless you have: 

• symptoms
• an increased risk of developing symptoms

Read about the symptoms of coeliac disease

When you should be tested for coeliac disease

Adults or children should be tested if they have the following signs or symptoms:

• persistent unexplained gastrointestinal symptoms, such as feeling sick and being sick
• slow growth
• feeling tired all the time
• unexpected weight loss
• severe or persistent mouth ulcers
• unexplained iron deficiency anaemia, vitamin B12 or folate deficiency anaemia
• type 1 diabetes, at diagnosis
• autoimmune thyroid disease, at diagnosis
• irritable bowel syndrome (IBS) in adults

You should have a test if you have a close relative with coeliac disease. This includes a parent, child, brother or sister.

Testing for coeliac disease

Testing for coeliac disease involves having:

• blood tests – to help identify people who may have coeliac disease
• a biopsy – to confirm the diagnosis

You'll need to eat foods containing gluten around the time you're  being tested. This is to make sure the tests are accurate. Avoiding gluten could lead to an inaccurate result.

Do not start a gluten-free diet until the diagnosis is confirmed, even if the blood test results are positive.

Blood test

Your GP will take a blood sample to test it for antibodies usually found in people with coeliac disease.

If coeliac disease antibodies are in your blood, your GP will refer you to a specialist. You may need to have a biopsy of your gut to confirm the diagnosis.

It is sometimes possible to have coeliac disease and not have these antibodies in your blood.

If the result of your blood test is negative, but you continue to have symptoms, you may need to have a biopsy.

Biopsy

You'll have a biopsy of your gut in hospital. 

The biopsy can help confirm a diagnosis of coeliac disease. It's usually done by a gastroenterologist. This is a specialist in treating conditions of the tummy and intestines.

What happens at your biopsy

An endoscope will be put into your mouth and gently passed down to your small intestine. An endoscope is a thin, flexible tube with a light and camera at one end.

Before the procedure, you'll get a local anaesthetic. This is to numb your throat. You may get a sedative to help you relax.

The gastroenterologist will pass a tiny biopsy tool through the endoscope. This is to take samples of the lining of your small intestine. The sample is then examined under a microscope for signs of coeliac disease.

Tests after diagnosis

If you're diagnosed with coeliac disease, you may also have other tests. These are to assess how the condition has affected you so far.

Follow-up blood test

You may have more blood tests to check the levels of iron and other vitamins and minerals in your blood.

This will help to find out if coeliac disease has led to you developing anaemia as the result of poor digestion. Anaemia is a lack of iron in your blood.

Skin biopsy

If it looks like you have dermatitis herpetiformis (an itchy rash), you may have a skin biopsy. This is done under local anaesthetic. It involves taking a small skin sample from the affected area. The sample is then examined under a microscope.

DEXA scan

Your GP may send you for a DEXA scan. This is a type of x-ray that measures bone density. It is only advised in some cases of coeliac disease. You might have one if your GP thinks your condition may have started to thin your bones.

Coeliac disease can lead to osteoporosis. This is when your bones become weak and brittle. It can happen because of poor digestion and your body not having enough nutrients. A DEXA scan will look to see how solid your bones are. It can help tell if you're at risk of bone fractures as you get older.

Local groups

Many people feel overwhelmed when they're first diagnosed with coeliac disease. Switching to a gluten-free diet can be confusing.

Many people accidentally eat foods that contain gluten after they get a diagnosis. This may cause their symptoms to return.

You can learn more about coeliac disease, suitable diets and find a local support group on the Coeliac Society of Ireland - coeliac.ie