Question: Do I have to re-introduce gluten in order to have an accurate gluten sensitivity test done?
Answer: Yes and No
If a person knows they are sensitive to gluten and have gone on a gluten-free diet, and want to know if they can have gluten again, then a challenge is in order (reintroduce gluten). THIS IS STRONGLY NOT RECOMMENDED. The gluten challenge has many cases of people who were damaged (some permanently) from the reaction to reintroducing gluten Even Small Amounts of Gluten Cause Relapse in Children With Celiac Disease, Journal of Pediatric Gastroenterology and Nutrition 34:2630, and it is no longer a requirement for diagnosing celiac disease Am J Clin Nut 1999;69:354-65.
Among 374 children in whom celiac disease was diagnosed before the age of 2, 5% developed an auto-immune disorder while on a gluten-free diet. Of those who went gluten-free, had years of no symptoms, then went back on a gluten-containing diet, 3.65% prevalence of systemic auto-immune disease with less than 12 months of eating gluten 9.1 % prevalence for 13-36 months of eating gluten again 26.3% prevalence for > 36 months of eating gluten again This means 1 out of 4 people who were sensitive to gluten, went gluten-free and eliminated all of their symptoms developed auto-immune diseases within 3 years of eating gluten again. Gastroenterology 1999;117:297-303.
If you know you are Gluten Sensitive, and you've gone on a gluten-free diet, and you want to know "am I better", then testing will confirm you are being successful in 'quieting down' the inflammatory cascade that occurs with gluten sensitivity and which sets one up for the development of autoimmune disease.
And if you want to 'throw the dice', if you want to gamble that you won't be the '1 out of 4' who develops an autoimmune disorder, then you would want to first check and make sure your tests are negative while being on a gluten-free diet, then do your gluten challenge and test again 1-2 months later. Once again, not recommended to do this.
Many people do not develop celiac disease until later in life. So even if one tests negative now, if they're genetically vulnerable, celiac disease can develop at any time as a result of the body no longer able to handle the stress of life. Something will be the 'straw that broke the camels back' and a person who has had negative tests in the past will begin producing the antibodies and begin the tissue destruction that will eventually manifest as Gluten Sensitivity and/or celiac disease. So in this scenario, these people want to know if they're genetically vulnerable.
The question is, am I sensitive to wheat? When a test looking at Gluten Sensitivity comes back positive, it tells us the immune system is reacting to an exposure to gluten. And if you are not eating gluten, it's one of a few things: