Diagnosis Dilemma: Eating Gluten Again to Test for Celiac Disease

To diagnose celiac disease, the only sure way to determine whether a person has it is with a blood test and biopsy. A definitive blood test and biopsy can only be performed when a patient is eating gluten. Test results for someone following a gluten-free diet for any length of time are rendered inaccurate.

Many people face a dilemma when they decide to go gluten-free diet first, before getting tested for celiac disease, and then feel better. Then, in order to be tested for celiac disease, they must start eating gluten all over again.

Getting sick to get tested

Some people are unwilling to make themselves sick in an attempt to distinguish between having celiac disease or benefitting from the gluten-free diet due to gluten sensitivity or for another reason. Social media is full of comments from people who say they will not risk their health or endure a return of symptoms to get that answer.

Experts at celiac disease centers routinely advise those who have symptoms or family members with celiac disease to be tested before starting a gluten-free diet. And celiac awareness organizations have been trying to spread that word, too.


Alessio Fasano, M.D., chief of the division of pediatric gastroenterology and nutrition at MassGeneral Hospital for Children in Boston and director of its Center for Celiac Research and Treatment, is outspoken about how serious it is to begin a gluten-free diet without testing. He has repeatedly drawn a comparison with the treatment for diabetes to make his point, saying no one would consider taking insulin because they have symptoms of the disease without first getting tested. 

The gold standard test for celiac disease is the anti-tissue transglutaminase (tTG-IgA) test. If this test is positive, it’s recommended that an upper endoscopy, in which six duodenal biopsies are taken, be done.

Accurate diagnosis provides real benefits for individuals and for the celiac disease population at large. Celiac disease involves complications that even gluten sensitivity does not, especially for those who cheat on the diet.


If someone knows they have celiac disease, they are often more motivated to keep to a strict form of the diet. And if the diagnosis rate for celiac disease, which currently stands at about 80 percent of those who actually have it, can be improved, money for research and interest in treatments and cures is likely to follow.

It’s just hard to see it that way when a return to a gluten-containing diet means weeks of facing returning symptoms that can be severe.

Recommendations vary on how long a patient must consume gluten, with the University of Chicago Celiac Disease Center advising 12 weeks of eating a half slice of bread or a cracker prior to blood tests and two weeks prior to a biopsy. The Celiac Center at Beth Israel Deaconess Medical Center says gluten should ideally be reintroduced for six to eight weeks. If the challenge is found to be intolerable, blood tests and a biopsy can be done earlier, but this can lead to a false negative result, according to the center.


These time frames can cause difficulties for patients. Cheryl Harris, a registered dietitian who specializes in celiac disease, says symptoms can develop early in the process.  

Why testing does not come first

One of the reasons people don’t get tested in the first place is that many frontline physicians seem unaware of the need and may recommend just trying the gluten-free diet, assuming it can’t hurt. 

The picture can be complicated further when a physician tests a patient for celiac disease when he or she is already following the diet, again unaware of the impact that has on diagnosis.

Jane Santucci, of Terre Haute, Indiana, knows this quandary well. After four years of stomach illness, her doctor told her she suffered from a common catch-all disease, irritable bowel syndrome. Santucci had already gone through a colonoscopy and upper endoscopy and says she was told her stomach lining was badly damaged and she should only eat low-fat foods.


When she heard a Super Bowl interview with NFL quarterback Drew Brees in which he talked about being gluten free, she wondered if gluten could be her problem, too. She decided to try the gluten-free diet.

Six months later her doctor tested her for celiac disease and the results were negative.  Santucci now has no intention of going back for more tests and is happy continuing to eat gluten free because she now feels fine. “I don’t have to feel self-conscious or rearrange my plans because of a crazy stomach,” says Santucci.  

While Santucci has no intention of consuming gluten again, celiac disease experts note that without a proper diagnosis patients put themselves at risk because they aren’t routinely screened for complications. They also don’t get proper nutritional support in the case of accidental ingestion, malabsorption issues or nutritional deficiencies.

Taking the challenge

Megan Stetzel of upstate New York did go through a gluten challenge and get tested even though she had originally put herself on the gluten-free diet after doctors couldn’t figure out what was wrong with her.


When Stetzel was 21 she started having severe digestive problems. She saw a primary care doctor, gastroenterologist and psychologist as she attempted to determine what was causing her to have diarrhea, heartburn, acid reflux, extreme weight loss, canker sores and loss of her fingernails. Eventually, she turned to the gluten-free diet.

Later her doctor recommended she consume gluten again to get a diagnosis, which she did for two weeks, during which she experienced numerous symptoms. “I felt awful,” she says. “It was very difficult to [eat gluten] thinking it was the issue…It was very mentally taxing.”

Her endoscopy and biopsy showed “irrefutable” evidence of celiac disease.


But sometimes patients who try to resume a gluten-containing diet and get properly diagnosed give up.

Kelly Thomas of Bogart, Georgia, originally went gluten free when her son was diagnosed with celiac disease about 5 years ago. Though blood work done at the time was negative, genetic testing showed she had the genes for celiac disease. Other family members, including her daughter, brother and niece, subsequently tested positive for celiac disease.

Thomas decided to go off the gluten-free diet in order to determine whether she, too, had the condition. She knew from her own research that she should eat gluten for 12 weeks, but her symptoms returned in half that time, and she had the blood tests done. The results were negative. Still Thomas is certain she has celiac disease, and she continues on the gluten-free diet. “I wish I had had the fortitude to continue for the recommended 12 weeks, ” she says.

Genetic testing        

Genetic testing is one option for those who are already gluten free and struggling with the thought of eating gluten again. Daniel Leffler, M.D., director of research at the Beth Israel celiac center, says the center routinely recommends genetic testing as a step toward deciding whether to move forward and go off the gluten-free diet to get an accurate celiac disease diagnosis.


Those who have celiac disease virtually always have the DQ2 and DQ8 genes, and genes are not affected by the diet. If you don’t have the genes, it’s nearly certain you don’t have celiac disease. If you do have the genes, it does not mean you do have celiac disease, only that the potential exits.

If the genes are present, the patient might seriously consider going off the gluten-free diet and getting further testing, Leffler says. But if the genes are not present, the patient might see less of a need. 

Overall those with a family history of celiac disease do have a greater chance of being screened early, sometimes before they are symptomatic and often before they have started a gluten-free diet.


Gluten sensitivity

Celiac disease experts are seeking celiac disease tests that would be accurate even if a patient is already on the gluten-free diet. Researchers are also looking for bio-markers to accurately diagnose gluten sensitivity.

Click here to learn more about gluten sensitivity.

Currently gluten sensitivity is a diagnosis of omission, coming after celiac disease and a wheat allergy have been ruled out through testing. The diagnosis is made after a gluten-free diet is initiated and symptoms improve. This process should take place under the direction of a physician.

Awareness is key

Diet is the only treatment for celiac disease and gluten sensitivity. That means it’s in the hands of patients more than doctors and drug companies. So perhaps it follows that patients, many frustrated by the ongoing symptoms and lack of answers, take diagnosis into their own hands, too.

It’s estimated that it still takes six to 10 years to get a celiac disease diagnosis. Patients and physicians, from family practitioners to gastroenterologists, all need to be aware of the importance of quick, accurate celiac disease testing in all cases that warrant it before the gluten-free diet comes into the picture.

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