Five to 10% of the normal population may exhibit low levels of thyroid antibodies with no symptoms of disease. The incidence is higher in women and increases with age. Other autoimmune disorders such as Sjogren`s syndrome, SLE, RA, and autoimmune hemolytic anemia may be positive for thyroid antibodies. Patients with myxederma, granulomatous thyroiditis, nontoxic nodular goiter, and thyroid carcinoma may occasionally produce thyroid antibodies.
The frequency of elevated results is higher with the thyroid peroxidase antibody. However, an elevated antithyroglobulin can be obtained while the thyroid peroxidase antibody results are normal. The presence of thyroid antibody may also be indicative of previous autoimmune disorders. Patients with slightly elevated thyroid antibody should be tested periodically, as the presence of the antibody may be an early sign of autoimmune disease. In active cases of thyroid autoimmune disease, and in some cases of thyrotoxicosis, moderate¿to high¿thyroid peroxidase¿antibody levels may be observed. The detection of very high levels in an individual with a firm, hard, fast-growing symmetrical goiter strongly suggests Hashimoto`s goiter. Serum demonstrating¿an elevated¿result should be interpreted in accordance with clinical findings. Diagnosis of thyroid autoimmune disease should not be made on the basis of the Thyroid Antibodies Test alone, but in conjunction with other immunological tests, thyroid function tests, physical examination, familial studies, and if necessary, biopsy.
Antithyroid Microsomal and Antithyroglobulin Antibody; Microsomal and Thyroglobulin Antibody; Thyroid Autoantibodies; Thyroid Peroxidase Antibodies; Anti-TPO; TPO Antibodies