The TPOAb test is used to diagnose autoimmune thyroid disorders, such as Hashimoto’s thyroiditis and Graves’ disease. These conditions occur when the immune system mistakenly attacks the thyroid gland, leading to inflammation and damage to the gland.

In Hashimoto’s thyroiditis, the thyroid gland is gradually destroyed by the immune system, leading to an underactive thyroid (hypothyroidism). In Graves’ disease, the immune system produces antibodies that stimulate the thyroid gland, leading to an overactive thyroid (hyperthyroidism).

The TPOAb test is also used to monitor the progression of autoimmune thyroid disorders and to assess the effectiveness of treatment.

A high level of TPO antibodies in the blood indicates that the immune system is attacking the thyroid gland, which can lead to thyroid dysfunction. The normal range for TPO antibodies varies depending on the laboratory that performs the test, but generally, a level above 35 IU/mL is considered to be high.