The traditional route for diagnosing coeliac disease starts with a blood test at your GP. This looks for certain antibodies that are produced in response to gluten. If this blood test suggests coeliac disease, then you will usually be sent for a gastroscopy (camera investigation of your small bowel), during which a biopsy will be taken to confirm the result. A biopsy involves the collection of tissue samples which can then be looked at more closely under a microscope.

However, sometimes, evidence of coeliac disease is seen during gastroscopy investigations undertaken for other reasons. If this is the case, do you still need a blood test to confirm your diagnosis and qualify you for gluten free on prescription (where available)? And how important is a biopsy?

In practice, a gastroscopy would rarely be used in isolation to see if someone is suffering from coeliac disease. A blood test that looks for coeliac-specific antibodies is an important (usually, first) step in the diagnosis process. A biopsy of the small intestine is also likely to be required in the majority of cases. It can be frustrating to know that your investigations showed possible evidence of coeliac disease, but be told to continue to eat gluten until you have had further tests to confirm it. However, it’s important to always follow the advice and instructions of your medical team.

Why Do I Need Still Need a Blood Test?

A blood test is important because it looks for antibodies produced by the immune system in response to eating gluten. These antibodies, known as IgA Tissue Transglutaminase (tTG-IgA) are strongly associated with coeliac disease. A positive result makes coeliac disease much more likely, but the result needs to be considered alongside your symptoms and, where necessary, further tests, such as a biopsy of the small intestine, in order to fully confirm a diagnosis of coeliac disease. 

How Important is a biopsy?

A biopsy of the small intestine allows doctors to look more closely at the health of your bowel and determine the level of damage present. In the case of coeliac disease, the endoscopist who performs the procedure will take samples of tissue from several different areas of the small intestine, these can then be studied under a microscope. New clinical guidelines mean that some people who have a very high level of coeliac antibodies in their blood (at least 10 times higher than the normal range) can be diagnosed without having a biopsy. However this decision will need to be discussed between you and your healthcare professional. 

Achieving a formal, accurate diagnosis of coeliac disease is important in order to access gluten free on prescription if it is provided in your area.

Why Do You Have to Keep Eating Gluten Whilst Being Tested for Coeliac Disease?

If you have had a gastroscopy that suggested coeliac disease, it will be very tempting to start to follow a gluten free diet to ease your symptoms. Many people feel relief from their symptoms in a very short space of time when they stop eating gluten.

However, it’s essential to continue consuming gluten regularly until all tests have been completed. If you stop eating gluten before completing the diagnosis process fully, then your body will stop producing the coeliac antibodies and your gut will begin to heal. This means that any further confirmatory tests, including blood tests and biopsies could be falsely negative.

Why is a Formal Diagnosis So Important?

A formal diagnosis is an important step in the treatment and support of people who have coeliac disease. A formal diagnosis comes with a number of benefits, including:

1. Access to check-ups and health monitoring – with your GP and/or gastroenterologist, including bone density scans to detect osteoporosis.
2. Access to expert dietitians – to support you as you move to a gluten free diet and ensure you are getting all the nutrients you need 
3. Access to gluten free food on prescription – covering a wide range of gluten free foods in Scotland, Wales and Northern Ireland, and bread and flour mixes in some areas of England.
4. A free Glutafin taster box – as soon as you have been formally diagnosed with coeliac disease, you can apply for your free Glutafin taster box, to try our delicious range of gluten free on prescription for yourself.

Don’t Put It Off

Coeliac disease is more common than you may think, affecting as many as one in a hundred people. So if you have symptoms of coeliac disease, such as diarrhoea, wind or abdominal discomfort, don’t just live with it. Talk to your GP and get tested for coeliac disease today. With a formal diagnosis and a switch to a gluten free diet, you could be feeling better fast.

Frequently Asked Questions

Q. Do I need a gastroscopy and biopsy to be formally diagnosed with coeliac disease?

A. Normally, yes, a blood test followed by a biopsy is seen as the gold standard for coeliac disease testing. However, the latest clinical guidelines now allow some patients whose blood test results show very high levels of antibodies to be formally diagnosed without a biopsy.

Q. What does a coeliac disease blood test look for?

A. Coeliac disease blood tests look for the antibodies produced by coeliacs in response to eating gluten. The test looks for IgA Tissue Transglutaminase (tTG-IgA), but also checks total immunoglobulin A levels

Q. Why do I need to keep eating gluten while being tested for coeliac disease?

A. If you stop eating gluten during testing, then your body will no longer produce the antibodies and the villi will recover. This can create a false negative result even if you have the disease.

Q. Do I need a formal diagnosis to get gluten free on prescription?

A. Yes. Gluten free on prescription is only available to people with a formal diagnosis of coeliac disease from their GP or gastroenterologist. Even then, availability is limited in England, with some Integrated Care Boards limiting gluten free on prescription to certain age groups and some not offering the service at all.

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