在甲亢症,通常是血清3,5,3′—三碘甲腺原氨(T_3)及甲状腺素(T_4)同时升高,但已知有时虽显示甲亢症的症状、体征,但仅血清 T_3值高而 T_4值正常,相反,亦有仅血清 T_4值高而 T_3值正常的情形。前者,确认为 T_3中毒之后,对病因、病理生理也有种种说法,诊断标准也被确定为一项独立的临床实体(clinical entity)来处理。与 In hyperthyroidism, usually serum 3,5,3’-triiodothyronine (T_3) and thyroxine (T_4) increased at the same time, but although it is sometimes known to show the symptoms and signs of hyperthyroidism, only serum T_3 T_4 value is high and normal, on the contrary, there are only serum T_4 value is high and T_3 value of the normal situation. The former, confirmed as T_3 poisoning, the etiology, pathophysiology, there are various claims, diagnostic criteria have also been identified as a separate clinical entity (clinical entity) to deal with. versus