Have you ever noticed recurring digestive discomfort, unexplained fatigue, or even mood swings that you can’t explain? Many people live with these symptoms without knowing that they could be related to their diet and immune system. For those seeking clearer answers about their gut health, testing for coeliac disease is key.
To perform it and obtain the maximum guarantee in your results, you can count on Ambar Lab. We work every day to answer these types of health questions through a very broad catalog, with more than 3000 types of laboratory tests, along with specialized support for professionals who need help in managing their activity and in the design and launch of new diagnostic projects. Without further ado, let’s look at all the details about the celiac disease test.
¿How does coeliac disease begin?
Coeliac disease is a chronic immune disorder triggered when a person with a certain genetic predisposition consumes gluten, a protein found in wheat, barley, rye and their derivatives.
In susceptible individuals, fragments of gluten reach the small intestine and the immune system interprets them as a threat. Certain genes then come into play, facilitating the presentation of these gluten fragments to immune cells, which promotes an inflammatory response that damages the intestinal mucosa and can cause villous atrophy, leading to poor nutrient absorption.
What test can I take to find out if I am coeliac?
When someone asks how to find out if they have coeliac disease, it is important to distinguish between several types of tests:
- genetic study (HLA-DQ2 and HLA-DQ8),
- blood antibody analysis (serological tests),
- and, in many cases, intestinal biopsy.
Genetic testing for coeliac disease is an important part of this set of tests, but it does not replace the others.
Genetic testing for coeliac disease
It analyses whether the person carries the HLA-DQ2 and/or HLA-DQ8 genes, or certain variants of these genes, which are associated with a higher probability of developing coeliac disease. The key points are:
- Around 90–95% of people with coeliac disease have HLA-DQ2 (especially the DQ2.5 variant), and most of the rest have HLA-DQ8 or a partial variant of DQ2.
- However, these genes also appear in a large proportion of the general healthy population (around 30-40% according to different series).
This means that:
- A positive result in the genetic test for coeliac disease (HLA-DQ2 and/or HLA-DQ8 present) indicates that the person has a predisposition and could develop the disease, but in no way confirms the diagnosis on its own.
- A negative result (absence of DQ2, DQ8 and risk variants) means that the probability of having coeliac disease is very low, with a negative predictive value of close to 99%.
That is why it is often said that genetic testing for coeliac disease is mainly used to rule out the disease, rather than to confirm it on its own.
Serological tests
Serological tests measure antibodies against components related to gluten or the intestinal immune response. The most commonly used in clinical practice are:
- anti-tissue transglutaminase antibodies (anti-TG2),
- anti-endomysial antibodies (EMA),
- antibodies against deamidated gliadin peptides (anti-DGP).
The antibodies mentioned are detected in blood and tend to rise when a person with coeliac disease consumes gluten.
Intestinal biopsy
Small intestine biopsy (usually from the duodenum) remains the gold standard for confirming the typical damage associated with coeliac disease in many adults.
During an upper gastrointestinal endoscopy, small fragments of intestinal mucosa are taken and analysed under a microscope to assess the presence of villous atrophy, increased intraepithelial lymphocytes and other characteristic changes.
What changes if you are coeliac?
This question often arises when someone considers getting tested for coeliac disease. It is useful to distinguish between three levels: genetics, antibodies and intestinal mucosa.
Genetic predisposition versus definitive diagnosis
In the field of genetics:
- If the person has HLA-DQ2 (especially DQ2.5) and/or HLA-DQ8, they belong to the group with the highest risk of developing coeliac disease throughout their life.
- However, only a small proportion of those who have these genes go on to develop the disease (around 2–5 per cent of carriers, according to studies).
Antibodies in blood
In people with active coeliac disease who consume gluten, the following tend to rise:
- anti-TG2,
- anti-endomisio,
- and/or anti-DGP.
When these antibodies appear clearly and consistently, the chances of the patient having celiac disease increase significantly, especially if they also carry the high-risk HLA genes. Some nuances must be considered:
- In young children, certain antibodies may take time to rise.
- In individuals with IgA deficiency, IgG isotype determinations are used.
- There are also false positives and false negatives, so antibodies are always interpreted within the clinical data set.
Intestinal mucosa
In a duodenal biopsy, a person with coeliac disease usually presents:
- shortening or disappearance of intestinal villi (villous atrophy),
- increase in intraepithelial lymphocytes,
- changes in the architecture of the mucosa.
Who should be tested for coeliac disease?
Who should be tested for celiac disease?
First-degree relatives of people with coeliac disease
Parents, children and siblings of coeliac patients have a higher risk of developing the disease, with prevalence rates close to 10% or even higher in some series.
Patients with atypical or confusing symptoms
Many people do not experience the “classic” chronic diarrhoea. In adulthood, it is common to find:
- persistent iron deficiency anaemia,
- bone disorders (osteopenia, osteoporosis),
- headaches, neurological disorders,
- fertility issues,
- recurrent oral aphthous ulcers,
- abdominal bloating, heavy digestion, or changes in bowel habits.
Individuals with equivocal or discordant serological results
In some patients, antibodies may:
- be positive but at low levels,
- show different results between different laboratories,
- or not consistent with clinical or biopsy findings.
Children and babies at higher risk
In paediatrics, genetic testing is mainly used in:
- children with first-degree relatives who have coeliac disease,
- paediatric patients with type 1 diabetes or other autoimmune diseases,
- cases with symptoms of malabsorption, weight stagnation or short stature in which coeliac disease is suspected.
How the test is performed
Genetic testing for coeliac disease is straightforward for both the patient and the laboratory.
Sample type: blood or saliva
The determination of HLA-DQ2 and HLA-DQ8 genes can be done based on:
- a blood sample,
- or a saliva sample (collected with a swab or using a specific collector).
Laboratory procedure
Once the sample arrives at the laboratory:
- The DNA is extracted.
- Genes related to HLA-DQ2 and HLA-DQ8 are analysed using molecular biology techniques (e.g. real-time PCR or other HLA typing methodologies).
- A report is generated indicating:
- if the person carries DQ2, DQ8 or risk variants,
- the genetic risk category,
- and whether genetics are compatible or not with the development of coeliac disease, following the recommendations of scientific societies.
- if the person carries DQ2, DQ8 or risk variants,
Where can I get tested for coeliac disease?
Genetic testing for coeliac disease is carried out in laboratories specialising in clinical diagnosis and genetics.
At Ambar Lab, our goal is to make these types of tests available to both healthcare professionals (clinics, private practices, specialist centres) and patients seeking answers backed by scientific evidence. Our aim is to provide accurate, reliable and easy-to-interpret coeliac disease test results so that both doctors and patients can make informed decisions about the monitoring, diagnosis and management of the disease.
Your diagnosis, always accompanied
It is important to remember that genetic testing for coeliac disease should not be used in isolation to make a diagnosis, but rather in conjunction with medical history, specific antibodies and, where appropriate, intestinal biopsy. Any decision to start or maintain a gluten-free diet should be made in consultation with a healthcare professional experienced in coeliac disease.
At Ambar Lab, you’ll find a comprehensive catalog of over 3,000 laboratory tests, specialized support to help you better organize your practice, and close collaboration in designing new diagnostic projects aimed at improving the care you provide to your patients. Contact our team for more information about celiac disease testing. Our professionals will answer your questions, guide you through each step of the process, and help you understand your results.
