Most patients with Hashimoto's thyroiditis have which type of antibodies?

Patients with Hashimoto's thyroiditis predominantly have anti-thyroid peroxidase (anti-TPO) antibodies. These antibodies are directed against the enzyme thyroid peroxidase, which plays a crucial role in the synthesis of thyroid hormones. The presence of these antibodies is a hallmark of autoimmune thyroid disease and is commonly associated with thyroid dysfunction seen in Hashimoto's thyroiditis.

The body’s immune system mistakenly attacks the thyroid gland, leading to inflammation and impairment of hormone production. Measuring anti-TPO antibodies is often used in clinical practice to help diagnose Hashimoto's thyroiditis, as they are found in a significant majority of patients with this condition.

While anti-thyroglobulin (anti-TG) antibodies can also be present in Hashimoto's thyroiditis, they are typically found at lower frequencies compared to anti-TPO antibodies. TSH antibodies and thyroid-stimulating antibodies are not typically associated with Hashimoto’s; instead, they are more related to Graves’ disease, an entirely different condition characterized by hyperthyroidism. Thus, the most definitive and prevalent antibodies found in Hashimoto's thyroiditis are indeed the anti-TPO antibodies.