Celiac disease is a chronic autoimmune disorder affecting the small intestine due to an abnormal immune response to gluten, a protein found in wheat, barley, and rye. This response damages the intestinal villi, impairing nutrient absorption. Early and accurate diagnosis is crucial to avoid long-term complications, and immunological testing plays a pivotal role in this process. Importance of Immunological Tests: The modern diagnostic strategy for celiac disease relies primarily on immunological tests, which detect the presence of antibodies directed against gluten components or autologous tissue proteins. These tests are non-invasive, easy to perform, and highly sensitive and accurate. Key Immunological Tests Used: 1. Anti-tTG IgA Antibodies: These are the most widely used and accurate antibody tests and are considered the first line of testing. Elevated levels of these antibodies indicate a high probability of developing the disease, especially in patients who consume gluten. 2. Anti-EMA IgA (Anti-TTG): These antibodies are highly specific but more expensive and complex to perform. They are used to confirm positive Anti-TTG results. 3. Deoxydiamine gliadin antibodies (DGP IgG/IgA): These are used especially in children under two years of age or in cases of IgA deficiency. 4. Total IgA test: This test is used to check for immunoglobulin A deficiency and is essential to avoid false-negative results in Anti-TTG IgA and Anti-EMA IgA tests. Immunological tests versus biopsy: Although intestinal biopsy was once considered the gold standard for diagnosing celiac disease, immunological tests are now sufficient in some cases with typical symptoms and high positive results. However, biopsy is used to confirm the diagnosis in unclear or complicated cases. The Role of Immunological Tests After Diagnosis: Immunological tests are also used to monitor a patient's response to a gluten-free diet. A decrease in antibody levels over time is a good indicator of patient adherence and improvement. Conclusion: Immunological tests play a fundamental role in the diagnosis and monitoring of celiac disease. Thanks to their accuracy and effectiveness, these tests have become an indispensable tool in modern medical practice, especially when combined with clinical symptoms, family history, and additional investigations. Education about the importance of early diagnosis and adherence to the gluten-free diet remains the cornerstone of disease management. Al-Mustaqbal University, the leading university in Iraq.