Coeliac disease is a serious medical condition that must be managed for the rest of your life. It's therefore very important to be properly diagnosed by a doctor.
A medical diagnosis and appropriate testing is important to:
- exclude serious medical problems
- determine your diagnosis
- establish the best course of treatment.
It’s also important not to self-diagnose coeliac disease if you feel better when you remove gluten from your diet. Coeliac disease is an important cause of gluten intolerance, yet feeling better if you don’t eat gluten doesn’t mean you have the condition.
The first step to diagnosis is to make an appointment with your doctor to discuss all the potential causes for your symptoms. If your doctor suspects coeliac disease, they will request the appropriate tests to make sure you are properly diagnosed.
Keep eating gluten
You must keep eating foods that contain gluten until your diagnosis. This is because testing for coeliac disease is only accurate when gluten is still in your diet.
If you have started a gluten free diet then you will need to resume a normal diet for at least 6 weeks before you are tested. You will also need to eat a minimum of four slices of wheat-based bread for adults, and two slices for children, every day during this time. This is called a gluten challenge and will help to make sure your test results are reliable.
Blood tests are used to screen for coeliac disease. They measure antibody levels in your blood that your body has produced in response to gluten. Blood tests may not be as reliable in children who are less than 4 years old because their antibody levels can fluctuate. They may need a repeat test 3 months later.
You won’t be diagnosed with coeliac disease if you just have a positive blood test. Diagnosis is only confirmed with a small bowel biopsy.
Small bowel biopsy
A small bowel biopsy is essential to confirm the diagnosis of coeliac disease.
It involves a procedure called a gastroscopy (a thin flexible tube inserted through your mouth and into the first part of the small bowel) and takes about 10 minutes under a light anaesthetic sedation. This allows a specialist doctor called a gastroenterologist to collect several tiny samples (biopsies) of your small bowel. A pathologist then examines the biopsies under a microscope for signs of damage (villous atrophy).
A diagnosis of coeliac disease will only be made if the biopsy results are positive for the disease.
Genetic tests may be requested if the diagnosis of coeliac disease is uncertain. This can happen if the blood or small bowel biopsy results are not clear, or if you didn’t eat enough gluten to ensure the tests were reliable.
A negative genetic test for specific coeliac disease genes effectively rules out coeliac disease, but a positive test can’t diagnose the condition. They can only confirm if you have a genetic predisposition to coeliac disease.
These tests involve a blood test or a scraping from the inside of your cheek, and are not affected by the amount of gluten in your diet.
Alternative diagnostic methods
Beware of alternative diagnostic methods such as hair analysis, stool-based tests, iridology or Vega testing. These tests are unreliable, may delay diagnosis and lead to unnecessary and ineffective treatments.
Sources: Coeliac Australia (Diagnosis, Gluten sensitivity)
Last reviewed: August 2015