Diagnosis

Since the symptoms of other conditions can closely mimic coeliac disease, correct diagnosis can only be made by showing that the bowel lining is damaged. Trialling a gluten free diet does not provide a diagnosis of coeliac disease. Subsequent investigations whilst on a gluten free diet will render negative results (this includes both the serological testing [blood tests] and histological testing [biopsy] and may delay the diagnosis of another condition with similar symptoms). If you think you may have coeliac disease, have a close relative with the condition, or have been treated for anaemia on previous occasions, it is important to discuss it with you doctor.

Coeliac blood tests may be used for initial screening (“coeliac serology and IgA”). If the results are positive or if negative but there is still concern that it may be coeliac disease, a referral to a gastroenterologist will be necessary. The diagnosis must be confirmed by performing a gastroscopy (an endoscope is passed through the mouth into the small bowel), a procedure that allows tiny samples (biopsies) to be taken from the small bowel which can reveal if gluten is causing damage. A gastroscopy is done in a hospital or day-procedure centre while the patient is sedated (most people find it very straight forward). Taking small bowel biopsies is an essential part of diagnosing coeliac disease as the blood test alone is not definitive. A second biopsy is usually performed after about twelve months on a gluten free diet to show that repair of the damage has occurred.

If gluten has been excluded prior to testing, it will be necessary to reintroduce it to the diet at least six weeks prior to having the blood test and biopsy (the equivalent amount of gluten from four slices of standard bread daily for adults).

“At risk” groups, such as first degree relatives and people with type 1 diabetes, should be tested for coeliac disease.