The five tests of thyroid function include thyroxine T4, triiodothyronine T3, free thyroxine FT4, free triiodothyronine FT3, and thyrotropin TSH. If the results of these tests are abnormal, they may indicate hyperthyroidism or hypothyroidism. Clinically, hyperthyroidism may be characterized by emotional excitement and some corresponding symptoms in the nervous system, digestive system and circulatory system, such as hyperactivity or emotional excitement. Hyperthyroidism is manifested by increased appetite, increased meal size, and increased heart rate. In case of slow speech and movement or indigestion, constipation, loss of appetite and slowed heart rate are signs of hypothyroidism.