coeliac disease testing

Coeliac Profile

The coeliac profile test is one of several blood tests that may be used to help diagnose coeliac disease. Tissue transglutaminase IgA or IgG test is used as part of an evaluation for coeliac disease. Tissue transglutaminase is an enzyme that repairs damage in the body. People with coeliac disease often make antibodies that attack tissue transglutaminase. They are called anti-tissue transglutaminase antibodies or immunoglobin A (IgA) antibodies. Therefore, a blood test that shows higher levels of anti-tissue transglutaminase antibodies can give indication of possible coeliac disease or gluten sensitivity.

The immune system response in coeliac disease (a reaction against gluten, a protein found in wheat, barley, rye and oats) also involves the production of antibodies directed against an enzyme normally present in the intestines called tissue transglutaminase (tTG).  In coeliac disease, the body produces two types of antibodies that attack tTG. These are IgA and IgG. Measuring the IgA form of tTG antibody in the blood is more useful in detecting coeliac disease because it’s made in the small intestine where gluten causes inflammation and irritation in sensitive people.

Anti-gliadin antibodies are frequently found with anti-transglutaminase antibodies.  Anti-gliadin antibodies are produced in response to gliadin, a prolamin found in wheat.  Anti-gliadin IgA is found in approximately 80% of patients with coeliac disease. It is also found in a number of patients who are not enteropathic. Some of these patients may have neuropathies that respond favourably to a gluten elimination diet.

Coeliac Gene Test

Coeliac disease is defined as an immune-mediated systemic disorder elicited by gluten in genetically susceptible individuals. Gluten is a protein found in foods such as wheat, barley, rye and oats. Coeliac gene (HLA) testing is a useful test when the diagnosis of coeliac disease is unclear. This can occur if the blood results are difficult to interpret, or if adequate gluten was not being consumed to make the test reliable. It is performed on a blood test or cheek (buccal) scraping. As the gene test is not dependent on gluten intake, it can be used when people have already commenced a gluten free diet.

When testing might be required

There are often symptoms suggesting coeliac disease. These include chronic diarrhoea, abdominal pain, anaemia, weight loss, unexplained liver abnormalities or osteoporosis. When an infant is chronically irritable or fails to grow at a normal rate this can also be linked to coeliac; as well as family members with coeliac or hereditary connections. Additionally, in those with Type 1 diabetes, Down or Turner syndromes, there is around a 5-10% life time risk of developing coeliac disease.

Common symptoms associated with coeliac disease:

  • Bloating
  • Flatulence
  • Indigestion
  • Food sensitivities
  • Diarrhoea
  • Irritable bowels
  • Eczema or psoriasis
  • Chronic fatigue and fibromyalgia