Test Details: Thyroglobulin is a protein made by cells in the thyroid gland. This test is helpful in the determination of conditions like hypothyroidism and hyperthyroidism. A thyroglobulin test is mostly used as a tumour marker test to help guide thyroid cancer treatment and to detect any recurrence of thyroid cancer. The Thyroglobulin test is done prior to treatment of thyroid cancer, after the completion of treatment of thyroid cancer, before and after radioactive iodine therapy, to detect if there is recurrence of thyroid cancer, to monitor the effectiveness of treatment for conditions such as Graves disease.