It is useful in the diagnosis of thyroid autoimmune disorders. Differentiating thyroid autoimmune disorders from nonautoimmune goiter or hypothyroidism. As a diagnostic tool in deciding whether to treat a patient who has subclinical hypothyroidism. Disorders of the thyroid gland are frequently caused by autoimmune mechanisms with the production of autoantibodies. Anti-TPO antibodies activate complement and are thought to be significantly involved in thyroid dysfunction and the pathogenesis of hypothyroidism.