TPO and hypothyroidism: Age < 65 y TSH = 4.5–6.9 mIU/L treat if symptoms of hypothyroidism, positive TPO, planning pregnancy, progressively increasing TSH, goiter TSH = 7.0–9.9 mIU/L treat to decrease risk of stroke, CAD mortality TSH ≥10 mIU/L treatAge ≥ 65 y TSH 4.5–6.9mIU/L, no treatment TSH 7.0–9.9 mIU/L, treat to decrease risk of stroke, CAD mortality TSH ≥ 10 mIU/L treat