We know that to be tested for coeliac disease, we should keep eating gluten for an accurate result. When testing is done while on a gluten free diet, there is an increased chance of a false-negative or inconclusive result.The reason is that if a person has coeliac disease, the abnormalities in the level of antibodies and changes in the small intestine are dependent on gluten being ingested.
But some people have stopped eating gluten before being tested for coeliac disease. Individuals may choose start a gluten free diet before being formally diagnosed with coeliac disease for a multitude of reasons. These can include perceived health benefits, improved symptoms when eliminating gluten, and in some cases following advice from medical personnel or long wait times for medical appointments and access to endoscopy.
So can these people be tested for coeliac disease once gluten is removed from the diet, or is it too late?
Thankfully, it is not too late to be tested if the person wishes to do so. According to an article in the Expert Review of Gastroenterology and Hepatology by Ma et al (2013) (http://www.medscape.com/viewarticle/812075_4), the features of coeliac disease do not normalize immediately upon commencement of a gluten free diet. If the person has been following a gluten free diet for a short time (less than 1 month), abnormalities often remain and the person can be tested for coeliac disease.
However, if the gluten free diet has been followed for a longer period, and the blood test is normal, gluten must be re-introduced into the diet under medical supervision for testing to be done.
This is known as taking a gluten challenge.
How much gluten does one need to consume, and for how long before they can be tested?
More research is needed on this subject, but some recent studies have led to greater awareness.
In a study in Gut (http://www.medscape.com/viewarticle/805775_4), it was reported that a 14 day gluten challenge in which greater or equal to 3 g of gluten/day induces the changes needed for testing in the majority of adults with coeliac disease. The noted that sensitivity to gluten exposure varies greatly between individuals with coeliac disease and a small percentage of individuals had no significant changes after 14 days of significant gluten exposure.
So that would mean that one can start with 3g of gluten daily for 2 weeks. That is equal to 2 slices of bread daily.
If the initial challenge is tolerated, and if your doctor advises you to do so, a full gluten challenge of 3 g gluten per day for a further 6 weeks (total 8 weeks) can be performed, followed by duodenal biopsy (Ma et al, 2013).
Why get tested at all?
Some might argue that if a person feels better on a gluten free diet, they should not re-introduce gluten. They often state that a formal diagnosis is not important. They could be right in thinking that way, if a strict gluten free diet for life is followed with no ‘cheating’.
But in my opinion, it is important to get tested to distinguish between coeliac disease and non-coeliac gluten sensitivity. Coeliac disease is associated with many other auto-immune conditions and has long term complications if the diet is not followed. Also, with a coeliac diagnosis, comes regular follow up (hopefully), and care of complications.
In any case, it is always good to know our options and to make informed decisions together with our doctor.
It would be nice to know your opinion on this.
Note: If you find the thought of a gluten challenge distressing, there is hope. A new blood test is being developed to diagnose coeliac disease. Read about it here:
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