Description of the blood test:

Tissue transglutaminase (tTG) is an enzyme found in many tissues, particularly in the lining of the intestine. In people with Celiac disease (a genetic intolerance to gluten), the immune system perceives gluten as a threat and begins to produce antibodies against tTG. These antibodies attack the enzyme, leading to inflammation and damage to the small intestinal villi, which prevents the body from absorbing nutrients correctly. The tTG test is the most common and accurate primary screening tool for this condition.

What Does the Test Represent?

• Goal: To measure the level of IgA (or IgG) antibodies against tissue transglutaminase.
• Main Application: Screening for Celiac disease, diagnosing dermatitis herpetiformis (a skin manifestation of gluten intolerance), and monitoring adherence to a gluten-free diet.
• Method: Enzyme-Linked Immunosorbent Assay (ELISA).

Preparation Recommendations

• Timing: Blood should ideally be collected in the morning.
• Fasting: Overnight fasting (8–12 hours) is recommended; plain water is allowed.
• The Main Rule: Crucial: You must be on a gluten-containing diet (eating bread, pasta, etc.) for at least several weeks before the test. If you have already started a gluten-free diet, the antibody levels may drop to normal, leading to a false-negative result.

Factors Influencing the Result

• IgA Deficiency: Some individuals have a congenital IgA deficiency. In such cases, a standard tTG IgA test will be negative even if the disease is present. In these situations, a tTG IgG test is performed instead.
• Dietary Compliance: Even minor “cheats” on a gluten-free diet can maintain elevated antibody levels.
• Age: In children under 2 years old, the test may be less sensitive, so additional tests like Anti-Deamidated Gliadin Peptides (DGP) are often used.

When to Take This Test?

• Symptoms: Chronic diarrhea, bloating, stomach pain, growth delays in children, unexplained iron-deficiency anemia, or osteoporosis.
• Risk Groups: If a close relative has Celiac disease or if you have other autoimmune conditions (e.g., Type 1 diabetes or thyroid disease).

Medical Interpretation

• Crucial Note: Only a doctor can provide a final diagnosis. High antibody levels are strong evidence but usually require confirmation. Only a specialist can “fine-tune” the diagnosis by comparing results with your clinical state.
• Positive Result: Indicates a high probability of Celiac disease. Higher levels often correlate with more severe intestinal damage.
• Negative Result: Usually rules out Celiac disease, provided you were eating gluten and do not have an IgA deficiency.

Possible Further Investigations

• Total IgA: To ensure the body produces enough antibodies for the test to be valid.
• Anti-Endomysial Antibodies (EMA): A highly specific confirmatory test.
• Genetic Testing (HLA-DQ2/DQ8): To determine genetic predisposition.
• Small Bowel Biopsy: The “gold standard” for final confirmation and assessment of villous atrophy.
• Consultation with a Gastroenterologist.

When Does the Next Step Make Sense?

• If the test is positive, the next step is a consultation with a gastroenterologist to discuss a biopsy. If the diagnosis is confirmed, the primary treatment is a strict, lifelong gluten-free diet.
• All clinical decisions must be made by a healthcare professional based on laboratory findings and the clinical picture.

👉 If necessary, you can discuss the analysis results with a specialist such as a gastroenterologist  (Doctors – TAMC) or immunologist (Doctors – TAMC).