Coeliac disease is common, often missed, and very treatable once it’s diagnosed. This guide explains the symptoms, who should be tested, how testing works in the UK (including the important rule about not stopping gluten too early), the new UK guidance on diagnosis without a biopsy, and what living gluten free really involves.
Key points
- Coeliac disease is an autoimmune condition. Eating gluten makes the immune system damage the lining of the small bowel.
- About 1 in 100 people in the UK have it, but many haven’t been diagnosed.
- Keep eating gluten until testing is finished. Cutting it out early can make the tests falsely normal.
- The first test is a simple blood test. Adults with a positive result should see a gastroenterologist, and many have a gastroscopy with biopsies.
- Treatment is a strict, lifelong gluten-free diet, which usually lets the gut heal.
What is coeliac disease?
Gluten is a protein found in wheat, barley and rye. In coeliac disease, gluten triggers the immune system to attack the lining of the small bowel. The tiny finger-like projections that absorb food (villi) become flattened, so nutrients such as iron, folate and calcium aren’t absorbed properly.[1,7]
It isn’t an allergy or an intolerance. It’s an autoimmune condition, and it tends to run in families. About 1 in 100 people in the UK are affected, but only a minority have been diagnosed.[1,7]
Symptoms
Symptoms vary a lot. Some people have obvious gut symptoms, others have none, and many have symptoms for years before anyone thinks of coeliac disease.
- diarrhoea, or sometimes constipation
- bloating, wind and tummy pain
- tiredness
- unexplained iron deficiency anaemia, or low B12 or folate
- weight loss
- mouth ulcers
- an itchy, blistering rash, usually on the elbows, knees or buttocks (dermatitis herpetiformis)
- tingling or numbness in the hands and feet, or problems with balance (less common)
Because the symptoms overlap with IBS, NICE recommends a coeliac blood test for anyone with IBS-type symptoms before IBS is diagnosed.[1]
Who should be tested?
NICE recommends offering testing to people with:[1]
- persistent unexplained gut symptoms, such as tummy pain, bloating, diarrhoea or constipation
- ongoing tiredness or unexplained weight loss
- iron, B12 or folate deficiency
- type 1 diabetes or autoimmune thyroid disease
- a parent, child, brother or sister with coeliac disease
If a close relative has coeliac disease, your own risk is about 1 in 10.[7]
See your GP promptly if you have:
- unexplained weight loss
- blood in your poo
- difficulty swallowing, or persistent vomiting
- severe or night-time diarrhoea
These need checking whatever the cause. If you’re losing a lot of blood or feel very unwell, call 999 or go to A&E.
How coeliac disease is diagnosed
Keep eating gluten until testing is complete
Have gluten in more than one meal every day (for example bread, pasta or cereal) for at least 6 weeks before the blood test.[1,3] If you’ve already cut gluten out, tell your GP. You may need to reintroduce it (a “gluten challenge”) before testing.
Step 1: the blood test
Your GP will test for an antibody called tissue transglutaminase (tTG), along with your total IgA level, which checks the test can be trusted.[1,3] A positive result means coeliac disease is likely, but in most cases it doesn’t confirm it on its own. A negative result while you’re eating gluten makes coeliac disease unlikely, although your doctor may still refer you if your symptoms strongly suggest it.
Step 2: seeing a specialist
If your blood test is positive, you should be referred to a gastroenterologist.[1] Traditionally, the diagnosis is confirmed with a gastroscopy, when small samples (biopsies) are taken from the first part of the small bowel (duodenum). Biopsies are painless. Some units offer a thinner transnasal endoscopy, which can also take duodenal biopsies.
Diagnosis without a biopsy
Updated British Society of Gastroenterology guidance (2026) allows some adults to be diagnosed without a biopsy, if they have symptoms, a very high tTG level (at least 10 times the upper limit of normal) and no warning signs, after discussion with the specialist.[2] A biopsy is still needed if you have warning symptoms, if something else might be going on, if you have low IgA, or if you’d simply prefer the certainty of a biopsy before committing to a lifelong diet. Your gastroenterologist will talk through which route suits you.
Get tested before you go gluten free
I take the biopsies that confirm coeliac disease during gastroscopy, and I see how much difference a firm diagnosis makes to the people who get one.
The thing I’d most like people to know is simple. Please don’t cut out gluten before you’ve been tested. I understand the temptation, especially if bread seems to make you feel worse, but once gluten is gone the blood test and biopsies can look normal, and getting a clear answer then means eating gluten again for weeks.
A firm diagnosis is worth having. It gets you the right follow-up, checks on your bones and blood, testing for your family, and the motivation to stick with the diet properly, which is what lets the bowel heal.
Ben JohnsonAdvanced Clinical Practitioner, Gastroenterology
Treatment: a gluten-free diet
The only treatment is a strict gluten-free diet for life. Even small amounts of gluten can keep the gut inflamed, even if they don’t cause symptoms.[1,7]
- Avoid wheat, barley and rye, and foods made from them, such as most bread, pasta, cakes, biscuits, pastry and beer.
- Oats are naturally gluten free but are often contaminated. Choose oats labelled gluten free. Most people with coeliac disease can eat them.[1]
- Naturally gluten-free foods include rice, potatoes, corn (maize), fresh meat, fish, eggs, fruit, vegetables, pulses, milk and cheese.
- Ask for a referral to a dietitian, who can make the change much easier.[1]
Reading labels
By law, cereals containing gluten must be highlighted in the ingredients list of pre-packed food, usually in bold. A food can only be labelled “gluten free” if it contains 20 parts per million of gluten or less, a level that’s safe for people with coeliac disease.[4] “May contain” warnings are voluntary, so check with the manufacturer or Coeliac UK if you’re unsure.
At home and eating out
- Use a separate toaster or toaster bags, and keep separate butter and spreads to avoid crumbs.
- Clean chopping boards, colanders and worktops before preparing gluten-free food.
- Restaurants and cafés must be able to tell you which dishes contain gluten. Ask how food is prepared, particularly anything fried in shared oil.
- Coeliac UK has a food and drink guide and an app that make shopping much easier.
Gluten-free food on prescription
In England, gluten-free bread and flour mixes can be prescribed, but some local health boards have stopped or limited prescriptions, so it depends on where you live. Scotland, Wales and Northern Ireland have their own arrangements.[5] Ask your GP or check with Coeliac UK.
After diagnosis
- Most people feel better within weeks, although the gut can take months or longer to heal fully.
- You should have a yearly review with your GP or a dietitian, including a repeat blood test to check you’re keeping gluten out.[1]
- Your doctor may check your iron, folate, B12, vitamin D and bone health. Some people are offered a bone density scan.[1,6]
- Close family members (parents, children, brothers and sisters) should be offered testing.[1]
Possible complications
Untreated coeliac disease can lead to anaemia, thinning bones (osteoporosis) and, rarely, some types of bowel cancer and lymphoma. Following a strict gluten-free diet greatly reduces these risks.[1,7] If symptoms continue despite the diet, the most common reason is hidden gluten, so a dietitian review is the first step. Your specialist will look for other causes if needed.
Frequently asked questions
Is coeliac disease the same as gluten intolerance?
No. Coeliac disease is an autoimmune condition that damages the bowel and can be confirmed with tests. Some people without coeliac disease feel better eating less wheat, but that’s a different condition, and it doesn’t cause the same damage.
Can I just try a gluten-free diet and see?
It’s better not to before testing. Going gluten free first can make the tests falsely normal, and then the only way to know for sure is to eat gluten again for 6 weeks or more.
Will I need to avoid gluten for ever?
Yes. Coeliac disease doesn’t go away. A strict gluten-free diet keeps it under control and lowers the risk of long-term problems such as anaemia and thinning bones.
Can I drink beer?
Most beers contain gluten. Gluten-free beers are widely available. Wine, cider, spirits and most liqueurs are gluten free.
Should my children be tested?
Yes. Parents, children, brothers and sisters of someone with coeliac disease should be offered a blood test, even if they don’t have symptoms.
References
- NICE. Coeliac disease: recognition, assessment and management (NG20). 2015. https://www.nice.org.uk/guidance/ng20
- Penny HA, et al. British Society of Gastroenterology guidelines on the diagnosis and management of coeliac disease in adults. Gut, published online July 2026. Summarised in: GI & Hepatology News, August 2026. https://news.gastro.org/issues/2026/august-2026/uk-guideline-opens-a-nobiopsy-path-to-celiac-diagnosis/
- Coeliac UK. How to test: adults (guidance for healthcare professionals). https://coeliac.org.uk/healthcare-professionals/diagnosis/how-to-test
- Coeliac UK. The law on gluten free. https://coeliac.org.uk/gluten-free-diet-and-lifestyle/food-shopping/law-on-gluten-free
- Coeliac UK. Gluten-free foods: a revised prescribing guide. https://www.coeliac.org.uk/document-library/378-gluten-free-foods-a-revised-prescribing-guide/
- Snook J, et al. British Society of Gastroenterology guidelines for the management of iron deficiency anaemia in adults. Gut 2021;70:2030–2051. https://gut.bmj.com/content/70/11/2030
- NHS. Coeliac disease. https://www.nhs.uk/conditions/coeliac-disease/