Gluten intolerance

Why the test of anti-gluten antibodies from the blood serum is an appropriate diagnostic step

1. A blood test quickly points to possible celiac disease as the cause of digestive problems, but it can also manifest itself in anemia, weight loss, fatigue, joint pain, skin rashes or lactose intolerance (3).
2. The essence is the determination of specific IgA antibodies against tissue transglutaminase, which is the first step in the diagnosis of celiac disease after anamnesis and clinical examination, followed by a biopsy of the mucosa of the small intestine (4) (5).
3. The determination of IgA antibodies from the blood is best done without dietary restrictions, without omitting foods containing gluten, otherwise it could cause false negativity (2).
4. You will receive the test result within 7 working days.
5. Examination for celiac disease/gluten intolerance is also suitable for children and adults, regardless of age.

When is it appropriate to take a serological test for celiac disease/gluten intolerance?

In celiac disease, the immune system creates antibodies in the fight against gluten. These antibodies in the intestine "mistakenly" attack tissue transglutaminase, which is normally involved in the metabolism of gluten (the so-called deamination of gliadin) (6). This autoimmune reaction causes a number of unpleasant symptoms. It is advisable to undergo a test for celiac disease/gluten intolerance if you experience any of the following symptoms after eating foods containing gluten:

Gastrointestinal:

• abdominal pain,
• bloating and/or flatulence,
• diarrhea and/or constipation,
• nausea and/or vomiting (7).

Extraintestinal:

• anemia,
• fatigue and headaches,
• joint pain,
• concentration problems, anxiety, depression,
• skin manifestations (rash) (7).

In addition to the above symptoms, we recommend that you undergo an examination, even if you have someone in your family who suffers from celiac disease, or if you have an autoimmune disease - type 1 diabetes or Hashimoto's thyroiditis (2).

Many people with gluten intolerance also have irritable bowel syndrome (IBS). Examination of antibodies against tissue transglutaminase IgA is essential to confirm/disprove whether celiac disease/gluten intolerance or another multifactorial disease is really hidden behind these symptoms (2) (8) (9).

Gluten intolerance or celiac disease

What else you should know before taking a serological test for celiac disease/gluten intolerance

There is a difference between gluten intolerance and celiac disease, although they are mistakenly confused and have similar symptoms that arise after eating grain foods. Sarmed Sami, a gastroenterologist at Mayo Clinic Healthcare in London, answered the question of what is the difference between these terms. "Consumption of gluten, a grain protein found in wheat, barley, rye and other grains, triggers a severe autoimmune reaction in celiacs that damages the cells of the small intestine. With gluten intolerance, cell damage and inflammation do not occur. It's more about hypersensitivity. If you have an immediate reaction after eating gluten (most often in the form of diarrhea), you suffer from gluten intolerance rather than celiac disease, which is characterized by a slow process, and you don't have a chance to feel it immediately." (10)

In the case of gluten intolerance, it is usually enough to limit the intake of gluten in food and the gastrointestinal symptoms will be reduced or disappear completely. "However, it depends on the degree of intolerance. For some, it is enough to cut the dose of gluten in half, for others, it is necessary to limit it more," says Sami. "This is the difference from celiac disease, where the patient must be strictly, completely and lifelong gluten-free." Diagnosing gluten intolerance and celiac disease traditionally begin with a blood test that determines whether the body considers gluten to be an intruder and creates antibodies against it. If the serological test is positive, an endoscopy and biopsy will be performed, that is, a tissue sample will be taken, from which the degree of damage to the small intestine will be determined. "Without a clear diagnosis of celiac disease, there is no reason to exclude gluten from the menu," concludes Sami (10).

What´s measured

About celiac disease and diseases associated with gluten

In connection with gluten-associated disorders, doctors recognize different medical terms that are often confused by the lay public, namely:

• an autoimmune-induced disorder is celiac disease (eng. Celiac Disease) (11),
• a disorder caused by an allergy is an allergy to gluten (IgE/nonIgE) (12),
• a disorder that is not caused by autoimmunity or allergy is gluten sensitivity or non-celiac gluten sensitivity (NCGS) (11).

The symptoms of gluten intolerance and celiac disease are similar, but fundamentally different, as we explained above. Celiac UK comes up with an even more detailed explanation:

• Celiac disease is not a food allergy or intolerance, it is an autoimmune disease.
• Allergy to gluten/wheat proteins is a reaction to proteins found in wheat and other grains, mediated by the immune system and occurring within seconds or minutes after consuming gluten.
• Non-celiac gluten sensitivity (intolerance) is a condition with symptoms similar to celiac disease, but with unclear involvement of the immune system because no antibodies are produced and there does not appear to be damage to the intestinal lining (13).

The question is how to determine individuals affected by celiac disease. Screening of asymptomatic individuals within the general population is not recommended (14).

TIP: Does celiac disease run in your family?

Professional publications recommend considering celiac disease screening in asymptomatic first-degree relatives of patients with a confirmed diagnosis of celiac disease (14) (15). Serological testing is recommended for people who have any of the following symptoms:

• Gastrointestinal symptoms:
  • chronic or recurrent diarrhoea or constipation,
  • unexplained weight loss,
  • abdominal pain, bloating.
• Other symptoms:
  • iron deficiency anemia after excluding other causes,
  • irritable bowel syndrome,
  • peripheral neuropathy, ataxia (16).

Tissue transglutaminase (tTG)-IgA antibody testing is the preferred test for detecting celiac disease in adults (17). As part of the test, the level of total IgA is also measured. In patients with IgA deficiency, an IgG test against deamidated gliadin peptides (DGP)-IgG is performed. An alternative approach is a test based on both IgA and IgG, especially tTG-IgA and DGP-IgG, in patients with a high probability of celiac disease.

The Gluten Intolerance package contains the following tests:

• Blood count with differential
  
  • It helps in the assessment of the overall health status, can assist in detecting anemia (low red blood cell count), and thus impaired oxygen supply to tissues, as well as in determining the risk of infections, inflammations, immune disorders, or coagulation problems.
• (tTG)-IgA, (tTG)-IgG
  • Antibodies against tissue transglutaminase class IgA, IgG belong to the basic examinations of celiac disease.
    
• (DGP)-IgA, (DGP)-IgG
  • Antibodies against deamidated gliadin class IgA, IgG represent an examination that has higher specificity and sensitivity compared to the determination of antibodies against natural gliadin, which was used in the past in the diagnosis of celiac disease. This test is used to screen for celiac disease in individuals with IgA deficiency, which affects 2 to 3% of celiac patients.
    
• Total IgA    
  • It is used to check for IgA deficiency, a condition that is often associated with celiac disease and can cause a false-negative tTG-IgA or EMA result. If you suffer from IgA deficiency, your doctor may order a DGP-IgG or tTG-IgG test.