Testing for coeliac disease and gluten intolerance
I often speak with people who believe they have issues with gluten or wheat products and self-diagnose themselves starting a gluten free diet without having being first tested for coeliac disease.
Not only do many people self diagnosed themselves, some doctors won't test for coeliac disease, instead telling someone to go gluten free and see how that goes, or to cut gluten out of their diet and then see how it goes.
Please don't listen to this advice, but instead go get tested properly for coeliac disease if you believe it is a concern or you.
How is coeliac disease diagnosed?
If someone suspects they have coeliac disease due to their symptoms, or has associated conditions such as thyroid problems, type 1 diabetes or close family members with coeliac disease they should first get an antibody blood test while gluten is still being eaten regularly. If the results are positive from that test, the second stage is to get a biopsy looking for damage to the gut which is what confirms a diagnosis of coeliac disease.
Genetic testing can exclude coeliac disease because if the genes HLA DQ2/8 are NOT present then it is 99.9% sure that someone definitely doesn't have coeliac disease.
It can't be used to diagnose coeliac disease because roughly 40% of the general healthy population can also have these genes.
Why you need to be eating gluten to get tested for coeliac disease
The tests used to diagnose coeliac disease rely upon the fact that an individual is eating gluten (found in wheat, barley and rye) regularly during their diet before taking the test.
Someone who has coeliac disease and is eating gluten will produce antibodies in their blood in response to that.
Take gluten out of the diet and those antibodies disappear and may not be found if a blood test is taken which can result in a false-negative result. The same thing occurs with the biopsy as the gut lining will begin to heal itself upon going gluten-free.
At present in the UK it is recommended that people are eating gluten in most meals every day for at least 6 weeks before getting the blood test and biopsy.
Why is it so important to be diagnosed with coeliac disease?
A complete diagnosis means that you are provided access to the full medical support, care and follow up that you require. People with coeliac disease have higher requirements for certain nutrients and have greater risks of long-term health effects like osteoporosis which is why part of follow up should include scans looking at bone mass.
Even if you were to follow a gluten-free diet, without a diagnosis you might be unaware of any nutritional deficiencies without adequate follow up from your GP, dietitian and healthcare professionals.
If not coeliac disease, then what?
The symptoms of coeliac disease can be quite vague for some, but not all people and overlap with other conditions including irritable bowel syndrome (IBS) or non-coeliac gluten sensitivity.
For IBS, approximately 70% of people find their symptoms improve on a low-FODMAP diet.
FODMAP stands for Fermentable, Oligo-saccharides, Di-saccharides, Mono-saccharides And Polyols which are fancy words for types of carbohydrates that aren't absorbed well in the gut by some people. FODMAPS include lactose, fructose, fructans (wheat) and can be found in a wide variety of foods including beans, milk, wheat and certain fruits and vegetables.
A person who responds to a low FODMAP diet may find that their symptoms improve on a gluten-free diet due to the removal of fructans found in wheat and continue excluding foods that aren't necessarily problematic for them.
There is lots of information on the internet about FODMAPs which isn't always accurate and up-to-date. If you want to see whether FODMAPS are problematic for you, you should always see a registered dietitian who has been trained in FODMAPS to help you appropriately exclude, test and then reintroduce.
What tests shouldn't be used to test for coeliac disease?
Unfortunately there are many companies out there these days trying to make money off people by 'diagnosing' their allergies, intolerances and even coeliac disease. Please, save your money and don't believe them!
You may end up restricting your diet unnecessarily again putting yourself at risk of nutritional deficiencies. These include (but are not limited to) hair analysis, IgG gliadin antibody tests, leukocytotoxic tests and vega tests.
These tests do not diagnose coeliac disease (and often other things they claim to diagnose) and are poorly regarded by experts within the allergy and intolerance field because of the lack of evidence behind their usage.
Gemma
Gemma Sampson APD
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