Tests For Celiac Disease and Gluten Intolerance/Sensitivity

By Amy Burkhart MD, RD

How do you test for celiac disease and gluten intolerance? The information on this topic can be dizzying. Let’s simplify it.

Celiac disease is an autoimmune condition that occurs in 1/100 people. Gluten is a protein found in wheat, barley, and rye. If someone with celiac disease eats gluten, damage occurs to their intestine. When celiac disease goes undiagnosed, problems such as other autoimmune conditions, vitamin deficiencies, osteoporosis, and even cancer can occur. A lifelong gluten-free diet is the treatment.

For these tests to be valid, a person must be consuming gluten at the time of testing.

• TTG IgA antibody plus Total Serum IgA. If the IgA is low on the initial test, you must do additional testing-see below.
• Deamidated Gliadin IgA antibody may or may not also be run at the same time.

For these tests to be valid, a person must be consuming gluten at the time of testing.

• TTG IgA, Total Serum IgA, DGP IgA

• TTG IgG, DGP IgG  ( the person must be on a gluten-containing diet for these to be accurate )
• Genetic Test For Celiac Disease

• The antibody testing ( TTG and DGP mentioned above) is not accurate on a gluten-free diet.
• A genetic screen for celiac disease can be done on a gluten-free diet. If it is negative- it eliminates the chance of ever having celiac disease.
• If it is positive, it does not mean you have celiac disease.- this is because forty percent of the general population carries one of the genes for celiac disease; only about 3% of them have celiac disease. Because of this, a positive genetic screen does not mean you have celiac disease. It only means you are susceptible to getting it.
• The genetic test is called HLA DQ-8, And HLA DQ-2 genetic test for celiac disease or Celiac Disease genetic screen.
• If someone has been on a gluten-free diet, a gluten-challenge can be done. If a gluten-challenge is done, antibody testing and possibly a biopsy will be needed at the end of the challenge.

The intestinal biopsy is the confirmatory test for celiac disease. It is recommended for all adults with positive screening tests for celiac disease. It may also be done in cases of high suspicion for celiac and normal labs. This situation may occur if other family members have celiac disease and symptoms are highly suspicious. A biopsy is not always needed for children. A no-biopsy approach is appropriate for children with TGA-IgA values ≥10 times the upper limit of normal and with appropriate tests and positive endomysial antibodies (EMA-IgA) in a second serum sample.

The biopsy is not perfect. It has several limitations. The physician must get 4-6 samples from different locations and include specific digestive tract parts. There is also room for error in the actual preparation and reading of the biopsy slides.

It is vital that the patient consume gluten when the biopsy is done and months prior. If the patient is on a gluten-free diet, the biopsy and labs will be falsely negative.

The American College of Gastroenterology now recommends that all patients diagnosed with IBS be screened for celiac disease before being given a diagnosis of irritable bowel syndrome.

Celiac patients need follow-up care. Click here for recommended guidelines for follow-up care for celiac patients.

After diagnosis, only 44% of patients saw a physician, and only 3% saw a dietitian for follow-up.  Please be proactive with your health. If your health care providers are not following up with you, take the initiative and make the appointment yourself.

The symptoms of gluten sensitivity( also called gluten intolerance by many) mimic celiac disease. You can not differentiate the two conditions without testing. There is no valid test for gluten intolerance. You eliminate the possibility of celiac disease by testing. If celiac tests are negative, but the person reacts to gluten, they are labeled “gluten-intolerant”.

The actual number of people with gluten intolerance s unknown because there is no diagnostic test for it. But gluten intolerance/gluten sensitivity is now recognized by the traditional medical community. This is validation for patients who, for years, have known gluten makes them sick but have tested negative for celiac disease.

Studies have looked at the small intestine of gluten-intolerant patients with an electron microscope. This is a powerful microscope not available at most hospitals. Intestinal inflammation was found in these patients. Something is going on in their intestine. There is a lot more to learn. This is a new and growing area of scientific study.

There currently is no valid test available for gluten sensitivity /gluten intolerance. It is diagnosed by first doing validated testing for celiac disease and wheat allergy. If those tests are negative, and the person gets ill from consuming gluten, they are then ” gluten intolerant.”

However, research has now shown that “gluten sensitivity” or “gluten intolerance” may actually not be due to gluten at all. People who think they are reacting to gluten, and don’t have celiac, may actually be reacting to other components of wheat.

Current research blames FODMAP carbohydrates and ATI proteins as two potential causes of “gluten sensitivity.” Given these are not “gluten” per se, there is a discussion to change this entity’s name to ” Non-celiac wheat sensitivity.” You will now see the terms “gluten intolerance, gluten sensitivity, non-celiac gluten sensitivity, and non-celiac wheat sensitivity” used interchangeably. There currently are no laboratory tests for either FODMAP intolerance or ATI protein reactivity.