Negative test results means that thyroid autoantibodies are not present in the blood at the time of testing and may indicate that symptoms are due to a cause other than autoimmune. However, a certain percentage of people who have autoimmune thyroid disease do not have autoantibodies. If it is suspected that the autoantibodies may develop over time, as may happen with some autoimmune disorders, then repeat testing may be done at a later date. Mild to moderately elevated levels of thyroid antibodies may be found in a variety of thyroid and autoimmune disorders, such as thyroid cancer, type 1 diabetes, rheumatoid arthritis, pernicious anemia, and autoimmune collagen vascular diseases. Significantly increased concentrations most frequently indicate thyroid autoimmune diseases such as Hashimoto thyroiditis and Graves disease.The Thyroid Antibody testing is done to assess & distinguish the Autoimmune thyroid disease from other form of thyroid disfunction, It consist thyroid peroxidase antibody (TPO) & Thyroglobulin antibody (TGAb), Thyroid autoantibodies develop when a person's immune system mistakenly targets components of the thyroid gland or thyroid proteins, leading to chronic inflammation of the thyroid (thyroiditis), tissue damage, and/or disruption of thyroid function. One or more of the following tests may be performed to help establish a diagnosis of and/or monitor an autoimmune thyroid disorder: Thyroid peroxidase antibody (TPO)?the most common test for autoimmune thyroid disease; it can be detected in Graves disease or Hashimoto thyroiditis. Thyroglobulin antibody (TGAb)? this antibody targets thyroglobulin, the storage form of thyroid hormones.Anti Thyroglobulin (Anti Tg), Anti Thyroid Peroxidase (Anti TPO)