Currently, there are no agreed upon methods for testing for gluten intolerance. There are, however, tests for celiac disease, an autoimmune disorder that triggers a significant allergic reaction to gluten. Without a validated test for non-celiac gluten sensitivity, many look into celiac testing.

Celiac disease is uncommon, affecting only 0.7 percent of the U.S. population. A negative test for celiac disease does not mean you do not have gluten intolerance.

Gluten is a protein in wheat, rye, and barley. It can also be found in some medications, lipsticks, and toothpastes.

In people with celiac disease, eating gluten causes the immune system to produce antibodies that attack the lining of the small intestine. Not only can this cause digestive system damage, but also it can prevent the body from getting important nutrients.

You can get a simple blood test to screen for celiac disease, but you must be on a diet that includes gluten for it to be accurate. The blood test screens for certain antibodies that are higher than normal for people with celiac disease.

A biopsy of tissue from the small intestine is the most accurate way to diagnose celiac disease. In the diagnosis process, your doctor will most likely start with a blood test, such as tTG-IgA.

If one of those tests indicates the possibility of celiac disease, you doctor might perform an endoscopy to view your small intestine and take a biopsy for analysis before having you make dietary changes.

One of the initial screens for celiac disease is the Tissue Transglutaminase IgA antibody test. According to the Celiac Disease Foundation, this test’s sensitivity is:

  • positive in about 98 percent for people who have celiac disease and are eating a gluten-containing diet
  • negative in about 95 percent for people who do not have celiac disease

For children around 2 years old and younger, the test will usually include Deamidated Gliadin IgA and IgG antibodies.

There is a minor chance for false-positive results for people who don’t have celiac disease but do have an associated immune disorder, such as rheumatoid arthritis or type 1 diabetes.

The IgA Endomysial antibody (EMA) test is typically reserved for people who are difficult to diagnose for celiac disease. It’s not as sensitive as the tTG-IgA test and is more expensive.

This test checks for IgA deficiency, which can cause a false-negative tTG-IgA or EMA result. If the test indicates that you have an IgA deficiency, your doctor might order a DGP or tTG-IgG test.

If you have an IgA deficiency or test negative for tTG or EMA antibodies, this test for celiac disease might be used. Although it’s unusual, if your tests are negative but the symptoms of gluten intolerance do not subside, talk with your doctor about other testing options or alternative diagnoses.

In the diagnosis process, your doctor might recommend genetic testing for human leukocyte antigens (HLA-DQ2 and HLA-DQ8). This can be used to eliminate celiac disease as a cause of your symptoms.

More than half of people with celiac disease continue to have symptoms even when they’re on a strict gluten-free diet, according to the Celiac Disease Foundation.

A commonly cited reason for this is unintentional gluten consumption. If you think that describes your situation, you can take an in-home urine or stool test to determine if you’ve consumed any gluten in the past 24 to 48 hours.

There are also in-home blood and DNA tests available for celiac disease testing. If you’re considering an in-home test, talk to your doctor about accuracy and potential risks. Also check to see if in-home testing is covered by your health insurance.

If you’re experiencing digestive discomfort or diarrhea for more than two weeks, talk to your doctor about your symptoms and consider asking about celiac disease screening.

The most common symptoms of celiac disease include:

Celiac disease symptoms that are not related to digestion can include:

If you feel that your digestive issues could be related to celiac disease, talk with your doctor. Even if you’re not concerned about celiac disease, if you have been experiencing digestive discomfort or diarrhea for over two weeks, make an appointment with your doctor.

If there is a suspicion of celiac disease, your doctor will most likely start the screening with a tTG-IgA test. The results of that test will direct whether more blood testing or genetic testing should be done.

Testing will often be followed by an endoscopy and biopsy before a gluten-free diet is recommended.