Hypothyroidism Diagnosis

The doctor will perform a physical exam and ask about your symptoms and medical/family history. Hypothyriodism is often found in families. The exam may reveal a goiter (enlarged thyroid), slow reflexes, dry skin, slow and hoarse speech, and/or a large tongue.

Your doctor may also do the following tests:

Blood Tests—Blood tests measure the level of thyroid hormones and thyroid antibodies. The diagnosis of hypothyroidism is made if the serum level of thyroid stimulating hormone (TSH) is elevated, and if the levels of serum free T4 (free thyroxine), and sometimes total T3, are low. These results mean that the thyroid gland is not making enough thyroid hormone.

The presence of thyroid antibodies may also signal autoimmune hypothyroidism, such as Hashimoto's thyroiditis, but is not needed for the diagnosis of hypothyroidism. The most common cause of hypothyroidism is autoimmune thyroiditis (Hashimotos).

Some blood tests performed for other reasons may raise suspicions about hypothyroidism and should be followed up, for example, blood tests that show high cholesterol, anemia, or low sodium.

• Screening for Hypothyroidism

References:

American Association of Clinical Endocrinologists website. Available at: http://www.aace.com/ .

Fatourechi V.Subclinical Hypothyroidism: An Update for Primary Care Physicians. Mayo Clin Proc. January 1, 2009 84:65-71

Harrison's Principles of Internal Medicine.15th ed. McGraw-Hill; 2001.

Thyroid Foundation of Canada website. Available at: http://www.thyroid.ca/ .

Surks MI, Ortiz E, Daniels GH, et al. Subclinical thyroid disease: scientific review and guidelines for diagnosis and management. JAMA.2004;291:228-38.