Indications for thyroid hormone replacement in nonpregnant adults with subclinical hypothyroidism*

TSH: thyroid-stimulating hormone; T4: levothyroxine; free T4: free thyroxine.
* Subclinical hypothyroidism is defined by a TSH above the normal reference range with a normal free T4, confirmed with repeat measurement.
¶ For patients not treated with T4, monitor TSH and free T4 initially at six months and, if stable, yearly thereafter.
Δ Convincing symptoms of hypothyroidism (new or worsening fatigue, constipation, cold intolerance) or growing goiter.