The additional tests that can be performed include thyroid antibodies test to diagnose autoimmune thyroid disease and distinguish it from other conditions of thyroid such as Graves disease, Hashimotos thyroiditis; calcitonin test to diagnose C-cell hyperplasia and medullary thyroid cancer; thyroglobulin test to primarily monitor the treatment and recurrence of thyroid cancer; and thyroxine binding globulin (TBG) test to evaluate the patients with abnormal levels of T3 and T4.