Coeliac Disease Diagnostic Testing Guide

Coeliac Disease Diagnostic Testing Guide: Why a medical diagnosis is important

It is important to get Coeliac Disease correctly diagnosed, in a timely manner. Coeliac disease is a serious autoimmune disease which if left untreated can have lifelong implications. Untreated Coeliac Disease leads to chronic systemic inflammation, poor nutrition and malabsorption of nutrients. Adopting to a gluten free diet prior to definitive diagnosis can make tests unreliable, resulting in incorrect results. But with a proper diagnosis you’ll have confirmation that your issues are caused by coeliac disease – plus peace of mind knowing that following the right dietary changes will reverse the damage and lead to a healthier you !!

Additional benefits of diagnosis

Being diagnosed with coeliac disease isn’t all bad news – it comes with the potential for a healthier and longer life! Following a strict gluten free diet can reduce long-term health risks associated with this diagnosis. It’s also important to have your immediate family members get tested as they, being first degree relatives have a high risk of also having the disease. Coeliac Australia have a wonderful hand out that you can print or email to family members which they can take to there doctors to explain why they need testing. Remember 80% of coeliac patients are undiagnosed, so more testing of those at high risk is the key. This, Family Screening Letter to the Doctor is included below.

How do I get diagnosed?

Managing a strict gluten-free diet is key for those with coeliac disease and can help to reduce long term risks. A proper diagnosis should be sought in order to ensure any associated conditions are detected, such as osteoporosis or other autoimmune diseases. It’s also important that relatives of people diagnosed carefully consider screening too – so everyone gets the care they need!

1. The symptoms of Coeliac Disease are very broad and overlap with many other conditions, this is why diagnosis rates are so low. A very handy tool for accessing your symptoms can be found on the Coeliac Australia website. Click here to do the assessment . If the assessment says Coeliac Disease is a possibility then move on to step 2.
2. The next step to diagnosis is to find a good doctor/gp, one that will listen to you and is willing to do some work to investigate the course of your symptoms. Some doctors have done extra training or have a particular interest in auto immune or gut related issues like coeliac disease, so they may be more helpful than say a GP who has an interest in sports health. If you are not getting answers with your current doctor, don’t give up- take your health into your own hands and find a new doctor and push until you get answers.
3. Before making any dietary changes, it’s important to make sure they are medically-sound and properly informed. If you’re considering a gluten free diet for yourself or your family, get tested first – you need to be consuming gluten to get reliable test, if you start gluten free diet before you get tested your results could be inaccurate! But if you’ve already made the switch, don’t worry – all is not lost. Ideally you would go back on a diet consuming gluten for six weeks prior testing. To get reliable results that would mean- adults need 4 slices of wheat based bread per day, in order to ensure maximum reliability with the tests used diagnose coeliac disease. You can read more about the gluten challenge here Gluten challenge fact sheet.
4. Have your doctor run the correct blood test to start the screening processs. Below is a hand out you can print and take with you to your doctor, it tells the doctor what tests to do and how to interupt them. Basically they will run a Coeliac serology, which includes- Transglutaminase-IgA (tTG-IgA), Deamidated gliadin peptide-IgG (DGP-IgG), and possibly also HLA-DQ2/8 genotyping (also known as Coeliac disease HLA typing, useful when screening high-risk individuals e.g. those with a positive family history). An elevated antibody response in the blood implies that you may have an issue with gluten: Coeliac disease. However, a positive result on your coeliac serology test doesn’t mean it’s definitely true – there are other steps to take!
5. If you had an elevated antibody response in your bloods, the next step and gold standard way of diagnosis is a small bowel biopsy. To do this you will be referred to a gastroenterologist who will perform a gastroscopy- a simple 10minutes procedure in which they examine the stomach lining and take a small sample. They take a small sample as bowel damage caused by this condition may not be visible to the naked eye, the samples are examined for any changes and will confirm if villous atrophy (characteristic of untreated coeliacs) has occurred. Again ensure you find a good gastroenterologist and ensure they will be taking a sample during the procedure. Some doctors rely on observing for visual changes and opt not to take the sample, this is not the correct way to diagnose and a samDon’t worry though, armed with all the info at hand we can make sure everyone gets accurate and helpful advice!

Gene Testing (HLA genes)

While a small bowel biopsy remains the gold standard for diagnosing coeliac disease, HLA Gene testing can be an effective tool when circumstances make accurate diagnosis difficult. Gene testing does not need the patient to be consuming gluten so is great in situations such as, in children that we are wanting a less invasive method of screening first or in patients who are unable to take the gluten challenge. It can be done through finger prick or cheek (buccal) scraping tests ordered by your local doctor and will determine whether someone carries genes associated with over 99% of cases of coeliac disease. However just because you have these genes doesn’t mean you automatically have the condition itself- it just means you do have a 1:40 chance of now having it so you should move onto the next steps of testing – blood work and a biopsy.

Positive family history and Children

If your child has a first degree relative with confirmed Coeliac Disease but has no other symptoms and is growing normally it is recommended to wait until they are 4 years of age before doing any testing. The reason for this is because the antibody blood tests are more accurate from this age and putting them through a blood test any earlier is not necessary. If the antibody blood test is negative at age 4, consider repeating the test every 3 years, to ensure a diagnosis is not missed. The coeliac gene test (buccal scrape) may be useful in cases with young children wanting to avoid invasive blood tests.  

Coeliac Disease Diagnostic Testing Guide: Source- Coeliac Australia

Coeliac Disease Diagnostic Testing Guide: Source- Coeliac Australia

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