Subclinical Thyroid Dysfunction: A Joint Statement on Management from the American Association of Clinical Endocrinologists, the American Thyroid Association, and The Endocrine Society

Abstract

Subclinical thyroid dysfunction is a common clinical problem for which there are many controversial issues regarding screening, evaluation, and management. Subclinical hypothyroidism is defined as an elevated serum TSH level associated with normal total or free T4 and T3 levels. The overall prevalence is 4–10% in the general population and up to 20% in women older than 60 yr (1–3). Several alternative names have been proposed to describe this condition and include compensated hypothyroidism, preclinical hypothyroidism, mild thyroid failure, and mild hypothyroidism. Although each term has subtle implications that may be more or less appropriate in various circumstances, we will use the term subclinical hypothyroidism in the interest of consistency with a recent publication that is the topic of this discussion. Subclinical hyperthyroidism is defined as low serum TSH levels associated with normal free T4 and free T3 levels. The prevalence is about 2%; it is more common in women, blacks, and the elderly (4, 5).