Blood tests: Blood tests are crucial for diagnosing Hashimoto's thyroiditis. The following tests are commonly ordered:
a. Thyroid-stimulating hormone (TSH) test: TSH is a hormone produced by the pituitary gland that stimulates the thyroid gland to produce thyroid hormones (T3 and T4). In Hashimoto's, the immune system attacks the thyroid, leading to reduced thyroid hormone production. As a compensatory mechanism, the pituitary gland releases more TSH to try to stimulate the thyroid. Therefore, elevated TSH levels are a common finding in Hashimoto's.
b. Free thyroxine (FT4) test: FT4 is a measurement of the active thyroid hormone (T4) in the bloodstream. In Hashimoto's, FT4 levels may be low due to decreased thyroid hormone production.
c. Thyroid peroxidase antibodies (TPOAb) test: This test detects the presence of antibodies against thyroid peroxidase, an enzyme found in the thyroid gland. TPO antibodies are present in most cases of Hashimoto's, indicating an autoimmune attack on the thyroid.
d. Thyroglobulin antibodies (TgAb) test: This test measures antibodies against thyroglobulin, a protein found in the thyroid gland. Tg antibodies are also elevated in Hashimoto's.