Thyroglobulin Antibody (Antithyroglobulin Antibody)

Overview:

Detect and confirm autoimmune thyroiditis, Hashimoto thyroiditis.

Thyroglobulin antibody results should be interpreted in light of the total clinical presentation of the patient, including symptoms, clinical history, data from additional tests, and other appropriate information.

The United States NHANES III survey reported a TgAb prevalence of approximately 10% for the general population, measured by competitive immunoassay.1 This study reported that 3% of subjects with no risk factors for thyroid disease had detectable TgAb without associated presence of thyroid peroxidase (TPO) antibodies.1 TgAb prevalence has been shown to be approximately twofold higher than normal for patients diagnosed with disseminated thyroid carcinoma (~20%).2,3 It has been suggested that low levels may represent "natural" antibody in healthy individuals or, alternatively, may represent underlying silent autoimmune thyroid disease.4 There is some debate over the clinical utility of serum TgAb measurement for assessing the presence of thyroid autoimmunity in areas of iodide sufficiency.4,5 In iodide-deficient areas, however, TgAb is believed to be useful for detecting autoimmune thyroid disease, especially for patients with a nodular goiter. TgAb measurements are also useful for monitoring iodide therapy for endemic goiter, since iodinated Tg molecules are more immunogenic. Sera samples were obtained in the United States for males <30 years of age following the criteria outlined by the National Academy of Clinical Biochemists (NACB) for establishing a normal reference range for thyroid tests.6,7 The screening criteria included serum TSH levels between 0.5 and 2.0 mIU/L, no personal or family history of thyroid disease, and absence of nonthyroid autoimmune disease. One hundred thirty-seven screened samples were tested, generating a 95% nonparametric upper reference limit below 4 IU/mL. Additionally, 519 samples were collected in the United States for both males and females ranging from 18 to 74 years of age. The screening criteria included serum TSH levels between 0.5 and 2.0 mIU/L, no personal or family history of thyroid disease, and absence of nonthyroid autoimmune disease. Of the 519 samples tested, 96% fell below 4 IU/mL.

1. Hollowell JG, Staehling NW, Flanders WD, et al. Serum TSH,T(4), and thyroid antibodies in the United States population (1988 to 1994): National Health and Nutrition Examination Survey (NHANES III). J Clin Endocrinol Metab. 2002 Feb; 87(2):489-499. PubMed 11836274

2. Spencer CA, Takeuchi M, Kazarosyan M, et al. Serum thyroglobulin autoantibodies: Prevalence, influence on serum thyroglobulin measurement, and prognostic significance in patients with differentiated thyroid carcinoma. J Clin Endocrinol Metab. 1998 Apr; 83(4):1121-1127. PubMed 9543128

3. Gorges R, Maniecki M, Jentzen W, et al. Development and clinical impact of thyroglobulin antibodies in patients with differentiated thyroid carcinoma during the first 3 years after thyroidectomy. Eur J Endocrinol. 2005 Jul; 153(1):49-55. PubMed 15994745

4. Ericsson UB, Chrisensen SB, Thorell JI. A high prevalence of thyroglobulin autoantibodies in adults with and without thyroid disease as measured with a sensitive solid-phase immunosorbent radioassay. Clin Immunol Immunopathol. 1985 Nov; 37(2):154-162. PubMed 3930112

5. Nordyke RA, Gilbert FI, Miyamoto LA,Fluery KA. The superiority of antimicrosomal over antithyroglobulin antibodies for detecting Hashimoto's thyroiditis. Arch Intern Med. 1993 Apr 12; 153(7):862-865. PubMed 8466378

6. Thyroglobulin Antibody II on the Beckman Access Coulter [package insert]. Brea, Calif: Beckman Coulter Inc; 2011.

7. Demers LM, Spencer CA. Laboratory medicine practice guidelines: Laboratory support for the diagnosis and monitoring of thyroid disease. Clin Endocrinol (Oxf). 2003 Feb; 58(2):138-140. PubMed 12580927