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Diagnosing Celiac Disease

Celiac Disease

Celiac disease can arise at any age creating damage to your intestines and starving your body of critical nutrients. With a range of symptoms commonly associated with other conditions, knowing if you are celiac, or simply have a gluten allergy or intolerance, is key to ensuring you’re on the right path to health.

How is the test performed?

Blood sample


Celiac disease is an autoimmune disorder triggered by eating grains that contain gluten such as wheat, rye and barley.

Over time, this autoimmune response to gluten can cause irreversible damage to the small intestine and prevent your body from absorbing nutrients critical for good health. About 1% of Canadians have celiac disease and it can appear at any age. While symptoms can vary greatly in adults, common symptoms include abdominal pain, flatulence and diarrhea. In children, they often have diarrhea and abnormal stretching of the abdomen, but may also show signs of malnutrition, anemia and failure to thrive. If celiac disease is diagnosed and treated early, the damaged tissues can heal, and you can reduce the risk of developing long-term complications.

Celiac symptoms and food intolerance or allergies can appear to be similar, but allergies and intolerances do not damage the lining of the intestine. It’s important to determine the causes of your symptoms so that you have the right care plan developed.

If a person has celiac disease, their body produces autoantibodies targeting self-antigens. 

LifeLabs offers a combination of two tests to aid in celiac disease diagnosis and monitoring:
  •  Anti TTG IgA
  • Anti Deamidated Gliadin IgG

While tTG IgA is the primary antibody produced in individuals with celiac disease, some people have an IgA deficiency which produces a false negative result. LifeLabs tTG IgA test automatically assesses IgA concentration to minimize the risk of false negatives, To aid in diagnosis and monitoring of IgA deficient patients, LifeLabs offers deamidated gliadin IgG antibody test as an alternate test.

You can be tested for celiac disease at any age. The symptoms are often nonspecific and variable, making the disease difficult to spot. You should speak with your doctor if you have a family history of celiac disease, or if you are experiencing one or more of the symptoms commonly associated with celiac disease including:

  • abdominal pain and bloating
  • chronic diarrhea
  • weight loss
  • extreme fatigue
  • flatulence
  • unexplained iron-deficiency anemia
  • joint pain

A physician may recommend a celiac blood test if you:

  • are exhibiting symptoms common associated with celiac disease
  • have a medical history that suggests celiac disease is a possibility
  • have a family history of celiac disease
  • have already been diagnosed with celiac disease and physician wants to monitor your tTG IgA and/or deamidated gliadin IgG antibody levels after gluten has been removed from your diet

A physician may also order a test if you have a condition that is known to be associated with celiac disease including:

  • Type 1 diabetes
  • Down syndrome
  • Thyroiditis
  • Arthritis
  • Depression
  • Neuropathy

Testing is completed by LifeLabs at a Patient Service Centre or via our mobile lab service (available in select cities) through a simple blood sample. You will require a completed test requisition from your healthcare provider.

Test results will be provided directly to your healthcare provider for discussion with you. The report will indicate:

  • Whether tTG IgA protein is present in your blood and the levels
  • Whether deamidated gliadin IgG protein is present in your blood and the levels

If your test results show the presence of either the tTG IgA or deamidated gliadin IgG antibodies, your healthcare provider may suggest additional testing before developing a treatment plan.


Celiac disease is an autoimmune disease whereby antibodies produced by the immune system recognize self antigens. We offer a combination of two tests to aid in the diagnosis of celiac disease: tissue transglutaminase (tTG) IgA antibody, and deamidated gliadin IgG antibody.  These tests may also be used for monitoring treatment effectiveness in patients with a confirmed celiac disease diagnosis.

Tissue transglutaminase antibody (tTG), IgA class

The primary test ordered to screen for celiac disease. It is the most sensitive and specific blood test for celiac disease and is the test recommended by the Canadian Celiac Association. This test may also be used to monitor treatment effectiveness, as tissue transglutaminase IgA antibody levels should fall once gluten is removed from the diet.

Deamidated Gliadin IgG antibodies

Around 2-3% of people with Celiac disease have an IgA deficiency. Depending on the testing method use, this may lead to a false negative result of the tTG, IgA test. The LifeLabs tTG IgA test assesses IgA concentrations and will indicate when IgA concentrations are low – minimizing the risk of false negative results.

If your patient is IgA deficient, deamidated gliadin IgG antibody testing may be used as an alternate for celiac disease diagnosis. The Deamidated Gliadin IgG antibodies test may be positive in some people with celiac disease who are negative for anti-tTG IgA, especially children less than 2 years old.

These tests may be carried out in addition to an endoscopy.  


Celiac Disease Testing

Samples for celiac testing may be taken at any of our Patient Service Centres. Patients must present a completed and signed requistion from a physician or healthcare provider

Please contact our customer care centre at 1-877-849-3637 (Ontario) or 1-800-431-7206 (British Columbia)

Results will be available to you within one week.

We have a wealth of medical experts available to support you in interpreting test results.
Consults with our experts are available upon request. Request medical consultation.

    Request more information

    The combination Celiac Disease testing panel, which includes anti TTG IgA and anti Deamidated Gliadin IgG, may be scheduled directly by the patient at any of our Patient Service Centres offering this service. They must have a requisition form completed by a physician or healthcare provider.

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