Learn what gluten intolerance is and the innovation of diagnosis in the impact of your well-being.

Gluten is composed of different prolamins (storage proteins) present mainly in wheat, but it can also be found in barley, rye, and oat. The term gluten intolerance can refer to three types of pathologies: autoimmune celiac disease, non-celiac gluten sensitivity and wheat allergy. 

Learn more about the differences in our article on intolerance and food allergy


Learn about Gluten and its relationship with celiac disease:

Celiac disease is an autoimmune disease, that is, the immune defense cells themselves attack the cells of the body, resulting in an inflammatory process that can develop in both children and adults.

In celiac disease, this inflammatory process occurs in the inner wall of the small intestine, leading to atrophy of the intestinal villi, causing decreased absorption of nutrients. 

Inflammation is induced by foods that contain gluten in people with the HLA-DQ2 (90% of cases) or DQ8 (6% of cases) haplotype. Gluten interacts with HLA markers, causing an abnormal mucosal immune response and tissue damage.

The diagnosis initially consists of serological testing for anti-tissue transglutaminase, anti-endomysium antibodies, anti-gliadin and Immunoglobulin A. If the serology is positive, it is necessary to perform a duodenal biopsy for diagnostic confirmation.


In children the most frequent symptoms are: 

  • Abdominal pain and distension;
  • Chronic diarrhea;
  • Vomiting;
  • Constipation;
  • Clear, fetid or fatty feces;
  • Iron deficiency anemia;
  • Weight loss;
  • Fatigue;
  • Irritability and behavioral issues;
  • Permanent tooth enamel defects;
  • Growth and puberty delay;
  • Short stature;
  • Growth deficiency;
  • Attention Deficit/Hyperactivity Disorder (ADHD).


In adults most frequent symptoms are: 

  • Unexplained iron deficiency anemia; 
  • Fatigue, pain in bones or joints;
  • Arthritis, osteoporosis or osteopenia;
  • Liver and biliary tract disorders (transaminitis, hepatic steatosis, primary sclerosing cholangitis, among others);
  • Depression or anxiety;
  • Peripheral neuropathy (tingling, numbness or pain in the hands and feet);
  • Seizures;
  • Migraines;
  • Changes in menstrual periods;
  • Recurrent infertility or pregnancy losses;
  • Mouth sores and dermatitis herpetiformis (itchy rash). 


Understanding non-celiac gluten sensitivity 

Non-celiac gluten sensitivity is diagnosed more often in adults than in children. The first cases of non-celiac gluten sensitivity (NCGS) were described as non-conclusive pathology with symptoms of abdominal pain, discomfort, abdominal bloating, changes in intestinal permeability and fatigue, with the possibility of Celiac disease being ruled out.

In this case, approximately 50% of individuals carrying the disease have a prevalence of HLA-DQ2 and/or HLA-DQ8 haplotypes. However, they do not have anti-transglutaminase antibodies identified. Therefore, gluten only triggered an immune response, leading to increased expression of interleukins, such as IL-6, IL-21, IL-17, and IFN-γ. 

It is speculated that the  microbiome may also participate in the pathogenesis of non-celiac gluten sensitivity. It is suggested that the composition of the intestinal microbiota and the metabolomic profiles may have an influence on the decrease of tolerance to gluten in genetically susceptible individuals. 

Patients with non-celiac gluten sensitivity also have nutritional deficiencies, other autoimmune diseases and decreased bone mineral density compared to the general population. 

Due to similar symptoms, such as abdominal pain, bloating, changes in intestinal permeability, diarrhea or constipation, cases of gluten intolerance have been recognized as Irritable Bowel Syndrome (IBS). 

In addition to intestinal symptoms, it is suggested that gluten-related peptides enter the systemic circulation and may cause neurological conditions such as ataxia, neuropathy, encephalopathy, depression, anxiety, autism, schizophrenia, and psychosis


Wheat allergy 

Wheat allergy is an immunoglobulin E (IgE)-mediated food allergy and is one of the eight main food allergies. 

When an allergen binds to IgE antibodies, it induces the activation of mast cells and basophils. In the case of wheat, it is assumed that the allergy occurs due to a change in oral tolerance and as a consequence of the type Th2 immune dysregulation that induces sensitization and B cell-specific allergen IgE production. 

Depending on the route of allergen exposure, wheat allergy can be classified as:

  • Occupational asthma (Baker’s asthma) and rhinitis;
  • Food allergy, with skin, gastrointestinal or respiratory tract involvement;
  • Wheat-dependent exercise-induced anaphylaxis; 
  • Contact urticaria. 

Wheat allergy is more prevalent in children, including symptoms such as moderate to severe atopic dermatitis, and wheat ingestion can cause urticaria, angioedema, bronchial obstruction, nausea, abdominal pain or, in severe cases, systemic anaphylaxis. 

In adults, gastrointestinal symptoms caused by ingestion may be mild and difficult to recognize, with diarrhea and bloating being the most common symptoms. 

Given this scenario, SYNLAB, in addition to providing serological dosages of anti-tissue transglutaminase antibodies, antiendomysium, anti-gliadin and immunoglobulin A, provides different tests of innovation including the analysis of gluten intolerance or wheat allergy. 


Gluten Intolerance Tests: Which one to do?

The tests that SYNLAB makes available for gluten intolerance analysis are:     


The Gluten Intolerance Test: Celia Test 

The Celia Test analyzes the HLA-DQ2 (associated with 90% of cases of gluten intolerance) and HLA-DQ8 (associated with 6% of cases of gluten intolerance) haplotypes, through a simple blood collection. 

The test is indicated for:

  • For patients with clinical suspicion and negative serological study, before performing a duodenal biopsy.
  • To investigate genetic susceptibility in family members of a celiac patient. 
  • Patients with positive serological studies.
  • Patients who follow a gluten-free diet without a correct diagnosis.
  • The cases in which there is reintroduction of gluten, after exclusion diet. 


See more about the SYNLAB Gluten Intolerance Test at: Celia Test – Genetic predisposition to celiac disease


Gluten and Lactose Intolerance Test: Intolerance 2      

The Intolerance 2 test allows to know in a single analysis, through a simple blood collection, if there is a genetic predisposition for celiac disease, by analyzing the HLA-DQ2 and HLA-DQ8 haplotypes and also for primary lactose intolerance by analyzing variant -13910C> T in the MCM6 gene, responsible for the production of the enzyme lactase, associated with 90% of cases of lactose intolerance.

The test is indicated for:

  • Patients with clinical suspicion of celiac disease and negative serological study, before performing a duodenal biopsy.
  • Patients with positive serology for celiac disease who reject duodenal biopsy.
  • Patients with symptoms compatible with celiac disease.
  • Patients with symptoms compatible with lactose intolerance.


See more about the SYNLAB Gluten and Lactose Intolerance Test at:  INTOLERANCE 2 – Age-related gluten and lactose intolerance


Wellness check

Through a simple blood collection, the Wellness Check test provides information on the genetic predisposition to the regulation of metabolism and other processes related to nutrition to adjust the diet in a customized way. In addition to performing the gluten intolerance analysis by analyzing the HLA-DQ2 and HLA-DQ8 haplotypes, it determines genetic variants in 24 genes related to: cholesterol and lipid profile, lactose intolerance, salt sensitivity, alcohol metabolism, caffeine metabolism, risk of osteoporosis; liver detoxification, oxidative stress, inflammatory response and homocysteine metabolism.

The test is indicated for:

  • People who want to maintain and improve their current health status, preventing, as far as possible, chronic diseases that are common in adulthood.
  • People with a family history of frequent diseases in adulthood.
  • People with neurological development disorders or chronic diseases, in order to improve their quality of life through nutrition.


See more about the SYNLAB test at: Wellness Check – The genetics of metabolism, nutrition and well-being


A200 test

The A200 test assesses IgG reactivity (hypersensitivity reaction) to gluten proteins and other 215 foods in the Mediterranean diet.  With a simple blood collection it is possible to know which foods can be potentially harmful to your health. 

The test is indicated for:

  • Gastrointestinal disorders: abdominal pain, constipation, diarrhea, abdominal bloating, nausea, acidity, ulcers and thrush, gastritis, colitis.
  • Dermatological processes: acne, eczema, psoriasis, itchy urticaria.
  • Neurological diseases: headache, migraine, dizziness, vertigo.
  • Respiratory changes: cough, bronchitis, asthma, rhinitis.
  • Psychological conditions: anxiety, depression, fatigue, hyperactivity.
  • Musculoskeletal disorders: pain, stiffness, arthritis, fibromyalgia.
  • Others: fluid retention and obesity.


See more about the SYNLAB A200 test at: A200 Test – Intolerance to more than 200 foods


Wheat Intolerance Tests: Which one to do?

The tests that SYNLAB makes available for wheat intolerance analysis are:



The ISAC test consists of the simultaneous determination of specific IgE antibodies to 112 allergenic proteins, present in more than 50 different allergens, including wheat, from a single blood sample (plasma or serum). The analysis allows to obtain an individual sensitization profile, and the results are classified into four categories: undetectable, low, moderate-high and very high reaction. 

The test is indicated for:

  • For individuals in whom there is no correlation between the positivity of conventional allergy tests and symptoms.
  • For complex cases with poor response to treatment.
  • To evaluate patients with idiopathic anaphylaxis.
  • To detect suspicious and non-suspicious sensitizations.


Which test should I choose to find out if I have gluten intolerance? 

As the term gluten intolerance can refer to three types of pathologies: autoimmune celiac disease, non-celiac gluten sensitivity to and wheat allergy, the indicated test must be evaluated by the specialist physician, considering the symptoms presented and the patient’s clinical history.

About the SYNLAB Group

The SYNLAB Group is a leader in providing medical diagnostic services in Europe, providing a full range of clinical laboratory analysis services to patients, healthcare professionals, clinics and the pharmaceutical industry. Resulting from the Labco and Synlab merger, the new SYNLAB Group is the undisputed European leader in medical laboratory services.

Subscribe to our newsletter\n

Subscribe to receive news about our exams