Anti-Tissue Transglutaminase Antibodies (Coeliac Disease)

This is an antibody test used to help diagnose coeliac disease.

What it is

Anti-tissue transglutaminase (anti-tTG) antibodies are proteins that your immune system makes. Normally, your immune system protects your body from harmful invaders like bacteria and viruses. However, in some people, the immune system can mistakenly attack parts of their own body.

In coeliac disease, the immune system reacts to gluten, a protein found in wheat, barley, and rye. When someone with coeliac disease eats gluten, their immune system produces antibodies, including anti-tTG antibodies. These antibodies then target a substance in the body called tissue transglutaminase, which is an enzyme involved in many cellular processes. This attack can lead to inflammation and damage in the lining of the small intestine.

The anti-tTG test measures the level of these specific antibodies in your blood.

Why it matters

The anti-tTG antibody test is a very useful screening tool for coeliac disease. If the test shows a high level of anti-tTG antibodies, it strongly suggests that coeliac disease might be present. This is because these antibodies are usually only produced when gluten is consumed by someone with the condition.

Coeliac disease is an autoimmune condition that can affect people of all ages. If left undiagnosed and untreated, it can lead to a range of health problems over time due to the damage to the small intestine, which impairs the absorption of essential nutrients. These can include malnutrition, anaemia, osteoporosis (weak bones), and an increased risk of certain other autoimmune conditions.

Therefore, identifying high levels of anti-tTG antibodies is an important step in diagnosing coeliac disease, allowing for timely management and prevention of potential long-term complications.

What can cause it to be high or low

A high level of anti-tTG antibodies in the blood is most commonly associated with coeliac disease, particularly when the person is still consuming gluten. The higher the level of antibodies, the more likely it is that coeliac disease is present and active.

It's important to note that the test is most accurate when you are still eating gluten. If you have already stopped eating gluten, the antibody levels may have started to fall, potentially leading to a false-negative result.

In some rare cases, other conditions might cause slightly elevated levels of these antibodies, but coeliac disease is by far the most common reason for significantly high readings.

A low or undetectable level of anti-tTG antibodies generally suggests that coeliac disease is unlikely to be present, especially if you have been eating gluten regularly. However, as mentioned, if you have already started a gluten-free diet, the levels might be low even if you do have coeliac disease.

Lifestyle factors that may help

For individuals diagnosed with coeliac disease, the cornerstone of management is a strict, lifelong gluten-free diet. This means avoiding all foods containing wheat, barley, and rye.

Topics to discuss with your healthcare team regarding lifestyle might include:

• Understanding gluten-free living: Learning how to identify gluten in foods, understanding cross-contamination risks, and finding suitable alternatives.
• Nutritional balance: Ensuring a varied and balanced diet to obtain all necessary nutrients, as some gluten-free products may be lower in certain vitamins and minerals.
• Social and emotional well-being: Adapting to a new way of eating can sometimes be challenging, and support networks can be beneficial.

Questions to discuss with your GP

If you are concerned about coeliac disease or have received a result for anti-tTG antibodies, here are some questions you might consider discussing with your GP:

• What does my anti-tTG antibody result mean in the context of my symptoms?
• If my anti-tTG antibodies are high, what are the next steps for diagnosis?
• Is it important for me to continue eating gluten before further tests?
• What are the potential long-term health implications of coeliac disease if it is diagnosed?
• Are there any other tests that might be helpful to confirm or rule out coeliac disease?
• What support is available to help manage a gluten-free diet?