Diagnosis of coeliac disease

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					Diagnosis of coeliac disease

What is coeliac disease?
Coeliac disease is an autoimmune condition that affects the small bowel. A permanent intolerance
to gluten in food results in damage to the small bowel. Gluten is found in wheat, rye, barley and
oats. Once gluten is removed from the diet the bowel starts to repair itself.

The Coeliac Society of Western Australia is a not for profit organisation that aims to enhance the
quality of life for all people requiring a gluten free diet. We do this through providing information
and support as well as raising awareness in the community.

Membership is available by application with a supporting medical practitioner letter. Details on
membership can be found in the Membership and Services Brochure on our website or by
contacting the office ( or 08 9470 4122).

Who should be tested?
Coeliac disease is recognised as affecting 1 in 100 individuals, although only 1 in 5 is thought to
be diagnosed. Coeliac disease should be considered in individuals with:
   • iron, foliate or vitamin B12 deficiency
   • lack of energy and tiredness
   • diarrhoea, constipation or both
   • abdominal pain, indigestion, bloating or wind.

A diagnosis of coeliac disease is more likely if you have the following:
   • Coeliac disease in the family
   • Thyroid disease
   • Type 1 Diabetes Mellitus
   • Down syndrome
   • Abnormal liver tests
   • Osteoporosis
   • Undefined neurological disorder
   • Infertility or recurrent miscarriage

Screening for coeliac disease
A blood test can be used to indicate the likelihood of a diagnosis of coeliac disease. Ask your GP
for “Coeliac serology” blood tests. The tests will normally check:
    • Tissue transglutaminase antibody levels
    • Total serum Immunoglobulin A levels

A positive test indicates that further investigation should be undertaken by a gastroenterologist.
If you have a negative test but have gut symptoms you may also benefit from referral to a

You must still eat adequate amounts of food containing gluten for these tests to be accurate. This
amount can vary between individuals however the equivalent of four slices of wheaten bread each
day is the usual recommendation.

       Do not take foods containing gluten out of your diet before testing is complete.
Interpreting Results
Research has shown that blood tests are a good predictor of coeliac disease; however a biopsy of
the duodenum (part of the small bowel) remains the recognised standard for diagnosis.

Having a gastroscopy, where a camera is inserted into the stomach and small bowel through the
mouth, may be daunting but advantages include:
   • review of your bowel by a gastroenterologist, a doctor who specialises in this area
   • diagnosis according to recognised criteria that will allow you to access services for people
      with a proven malabsorption disorder, such as bone density scanning
   • a baseline to review your progress in the future.

Some individuals can have negative test results but still have coeliac disease. This is because:
   • tests require you to be eating gluten containing foods. If you are not eating these in a
      significant amount tests will not work
   • some people are deficient in Immunoglobulin A; the antibody on which blood tests are
   • blood tests may be inaccurate in young children.

If your tests are positive then the treatment for coeliac disease is to follow a strict, life-long
gluten free diet. Following a gluten free diet should always be on the recommendation of a
medical practitioner.

Gene Testing
Nearly all individuals with coeliac disease have a specific gene type. The common gene types for
coeliac disease are either HLA-DQ2 or HLA-DQ8. Gene testing can therefore be used as an
additional test where blood tests or biopsy show inconsistent or inconclusive results.

A positive test, although not diagnostic, supports a potential diagnosis of coeliac disease. The
test may be useful:-
    • where individuals are already following a gluten free diet resulting in negative screening
    • blood tests or biopsy
    • to predict non-susceptibility, for example in children whose parents have coeliac disease.

As these genes are found in >99% of individuals with coeliac disease, the absence of them can
exclude coeliac disease as a diagnosis now and in the future.

      Do not take foods containing gluten out of your diet before testing is complete.

Reviewed: March 2008

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