The current “gold standard” tests for celiac disease include testing for celiac antibodies in patients’ blood and performing an endoscopy to obtain small bowel biopsies. In order for these tests to be accurate, one has to be eating gluten up until the time of testing. If a patient is already on the gluten-free diet when these tests are done, the diagnosis of celiac disease can easily be missed.
Since starting this page I’ve encountered many people who have decided that they’d like to be tested for celiac disease after starting on the gluten-free diet. Per the celiac disease experts, a “gluten challenge” must be performed in these cases to assist in the diagnosis of celiac disease. A gluten challenge requires eating foods containing gluten for a prescribed period of time prior to an endoscopy and/or blood testing for celiac disease. The length of time and amount of gluten that need to be consumed for a gluten challenge vary from source to source. Here are some examples of different recommendations for a gluten challenge (current as of July 5, 2014):
University of Chicago Celiac Disease Center: “For a gluten challenge we recommend eating 1/2 slice of bread or a cracker each day for the duration of the challenge. Prior to blood testing we recommend 12 weeks of eating gluten. Prior to an endoscopic biopsy we recommend 2 weeks of eating gluten. In the case of a severe reaction to gluten, a medical professional may opt to shorten the 12-week challenge and move immediately to an endoscopic biopsy.”
Celiac Disease Center at Columbia University: “In individuals who are willing to further pursue the question of whether they have celiac disease, we will advise a gluten challenge. This consists of ingesting at least 4 slices of bread a day for one to three months followed by an endoscopy and biopsy. There is no evidence that following antibody tests is beneficial in establishing a diagnosis of celiac disease because these tests are not sensitive in this setting.”
Celiac Disease Center at Beth Israel Deaconess Medical Center: “Gluten is reintroduced into the diet and after a period of time (ideally 6 to 8 weeks if the challenge can be tolerated for that long) blood tests and an intestinal biopsy are performed. If the gluten challenge is not tolerable for the full 8-week period blood tests and biopsy can be performed sooner but this can lead to a false negative result.”
In addition, Dr. Leffler and colleagues published a paper in 2013 showing that the majority of patients with celiac disease will test positive after eating >3g gluten/day for 2 weeks. A typical piece of wheat bread contains about 5g of gluten.
Despite all of the confusion, there is hope on the horizon for a shorter gluten challenge in the future. Researchers at the Walter and Eliza Hall Institute in Australia have been developing a blood test that measures gluten-reactive T cells, immune cells that increase in response to gluten in those with celiac disease, via cytokine release assays. In a pilot study published earlier this year, patients with celiac disease had a significant jump in blood levels of gluten-responsive T cells, compared to controls, after only 3 days of consuming gluten. Per Dr. Jason Tye-Din, one of the researchers working on this test, “We hope that larger studies can validate these findings and establish its role in the diagnosis of celiac disease.” For the sake of my gluten-light kids, and everyone else who is in a similar situation in regards to diagnosis, I hope he is right.
A press release regarding the study can be found here.
Out of curiosity, have any of you been diagnosed with celiac after doing a gluten challenge? If so, do you remember how much gluten you had to eat and for how long prior to testing?
Ontiveros N, Tye-Din JA, Hardy MY, Anderson RP. Ex-vivo whole blood secretion of interferon (IFN)-γ and IFN-γ-inducible protein-10 measured by enzyme-linked immunosorbent assay are as sensitive as IFN-γ enzyme-linked immunospot for the detection of gluten-reactive T cells in human leucocyte antigen (HLA)-DQ2·5(+) -associated coeliac disease. Clin Exp Immunol. 2014 Feb;175(2):305-15.