The doctor will ask about your symptoms and medical and family history. A physical exam will be done. 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 level of thyroid stimulating hormone (TSH) is elevated and the levels of T4 are low. This means that the thyroid gland is not making enough thyroid hormone.
The presence of thyroid antibodies may also point to autoimmune hypothyroidism, such as Hashimoto thyroiditis. It is not needed to diagnose hypothyroidism. The most common cause of hypothyroidism is autoimmune thyroiditis.
Some blood tests done for other reasons may raise concerns about hypothyroidism (such as blood tests that show high cholesterol, anemia, or low sodium). These tests may require follow up appointments with your doctor.
Fatourechi V. Subclinical hypothyroidism: an update for primary care physicians. Mayo Clin Proc. 2009;84(1):65-71.
Hypothyroidism (underactive thyroid). National Institute of Diabetes and Digestive and Kidney Diseases website. Available at: https://www.niddk.nih.gov/health-information/endocrine-diseases/hypothyroidism. Updated August 2016. Accessed February 20, 2017.
Hypothyroidism in adults. EBSCO DynaMed Plus website. Available at:http://www.dynamed.com/topics/dmp~AN~T115914/Hypothyroidism-in-adults. Updated July 12, 2016. Accessed February 20, 2017.
Surks MI, Ortiz E, Daniels GH, et al. Subclinical thyroid disease: scientific review and guidelines for diagnosis and management. JAMA. 2004;291(2):228-238.
Last reviewed February 2017 by James P. Cornell, MD Last Updated: 3/15/2015