The diagnostic process
The diagnostic process
Diagnosis of coeliac disease is generally straightforward. Once a decision is made to test for coeliac disease, a blood test (coeliac serology) is performed. If this result is positive, then a gastroscopy with small bowel biopsies is undertaken to definitively confirm the diagnosis by demonstrating the typical changes of villous atrophy and inflammation in the small bowel.
One of the most important aspects of diagnosis is thinking to test for coeliac disease in the first place. The presence of specific symptoms or signs or a family history of coeliac disease should prompt screening by your doctor. These issues include unexplained and prolonged gastrointestinal symptoms, fatigue, weight loss, nutrient deficiencies. the presence of other autoimmune diseases such as autoimmune thyroid disease or type 1 diabetes and problems such as infertility, liver disease and osteoporosis.
If gluten is still being consumed, then the first step to assessment is performing coeliac serology. This is a simple blood test that measures antibody levels that become elevated in people with coeliac disease who are consuming gluten. It is essential that the person being tested is currently consuming a diet containing gluten, otherwise screening for coeliac disease with coeliac serology and confirming the diagnosis with gastroscopy and small bowel biopsies both become unreliable.
If gluten has already been removed from the diet prior to testing, the best option is to undertake a gluten challenge prior to testing. Another option that can sometimes help is to perform the coeliac HLA gene test. A negative gene test can exclude coeliac disease without further testing. However, if the gene test is positive, a gluten challenge followed by testing will be still be required to establish the diagnosis. A gluten challenge involves consuming gluten for an extended period of time. Some recommendations suggest approximately four slices of wheat-based bread per day for 6 weeks, for adults, and for children approximately two slices for the same period. After the challenge, testing with serology and gastroscopy and biopsies is undertaken. Many people find gluten challenge difficult as it triggers adverse symptoms. New diagnostic approaches that overcome the need for prolonged gluten challenge are being developed.