How to diagnose Coeliac Disease?

Coeliac disease affects around 1 in 100 Australians, but many people are still undiagnosed.

Written by Kate Stoker, Principal Dietitian at Simply Nutrition Dietitians

What we often see in clinic is people living with ongoing gut symptoms, fatigue, or nutrient deficiencies without a clear diagnosis.

Getting properly tested for coeliac disease is important, because if it’s missed or misdiagnosed, it can lead to long-term health complications. If you’re dealing with ongoing gut symptoms, working with a stomach and bowel dietitian can help guide the process.

Coeliac disease is not just a food intolerance.

It is an autoimmune condition that can impact nutrient absorption, bone health, fertility, and overall wellbeing.

Common symptoms

• Bloating and abdominal pain
• Diarrhoea or constipation
• Iron deficiency or anaemia
• Fatigue or low energy
• Unexplained weight loss

Symptoms can vary significantly, and some people have very mild or no obvious digestive symptoms at all. This is where a dietitian experienced in coeliac disease and gut health can help connect the dots.

How coeliac disease is diagnosed

A proper diagnosis involves several steps. Skipping steps or removing gluten too early can lead to inaccurate results.

Many people remove gluten before testing, which can make diagnosis difficult or inaccurate.

1. Keep eating gluten before testing

This is one of the most important steps. If you have already removed gluten, you may need to complete a gluten challenge before testing.

• Typically involves eating the equivalent of 4 slices of bread daily
• Usually for at least 6 weeks before testing

2. Blood tests (coeliac serology)

Blood tests measure antibodies linked to coeliac disease, but they are only accurate if you are still eating gluten.

It’s important to understand that blood tests are a screening tool, not a final diagnosis.

3. Small bowel biopsy

If blood tests are positive, a biopsy is required to confirm coeliac disease.

You must continue eating gluten until this test is completed, otherwise results may not be accurate.

4. Gene testing

In some cases, genetic testing is used if results are unclear. It can help rule coeliac disease in or out when other tests are inconclusive.

Why proper diagnosis matters

Without correct diagnosis and management, coeliac disease can lead to long-term complications.

• Osteoporosis
• Iron deficiency
• Infertility
• Liver disease
• Increased risk of some cancers

How a dietitian can help

Once diagnosed, managing coeliac disease isn’t just about removing gluten. It’s about rebuilding nutrition, improving symptoms, and supporting long-term health.

• Addressing nutrient deficiencies
• Improving energy levels and gut symptoms
• Helping restore a healthy weight
• Building a balanced gluten-free diet

Need help managing coeliac disease?

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