The Chinese name for T3 is Triiodothyronine, T4 is Thyroxine and TSH is Thyrotropin. If T3 and T4 are normal and TSH is elevated in a thyroid function test, it may be subclinical hypothyroidism and it is recommended to consult a doctor. Subclinical hypothyroidism often has no obvious signs or symptoms, and may show symptoms of hypothyroidism, such as fatigue, fear of cold, dry skin, and low energy. Subclinical hypothyroidism has received attention in recent years because dyslipidemia caused by subclinical hypothyroidism can promote the occurrence and development of atherosclerosis. Some subclinical hypothyroidism can develop into clinical hypothyroidism. Currently, L-Tâ‚„ therapy is considered necessary in the following cases: hyperlipidemia, serum TSH >10 mU/L. Patients with abnormal indicators are advised to undergo additional tests to identify the cause of the disease and then treat the symptoms.