Frey H, Johannesen O, Kapelrud H, Sand T
Medical Department B, Aker Hospital, Oslo, Norway.
Acta Med Scand. 1987;222(2):163-7. doi: 10.1111/j.0954-6820.1987.tb10654.x.
An ultrasensitive thyrotropin (TSH) assay was used to determine how many of 65 patients with primary hypothyroidism on thyroxine (T4) replacement therapy had suppressed serum TSH. In 13 patients (20%) TSH levels less than or equal to 0.1 mIU/l were found, indicating an overdose of thyroxine. After correction of the dose, 48 patients had normal TSH values. Their mean dose of thyroxine was 119 micrograms/24 hours, and the appropriate replacement dose tended to decline with advancing age. The serum level of thyroid hormones during replacement therapy with thyroxine very imperfectly reflected serum TSH values. It is concluded that overdose of thyroxine is common when suppressed serum TSH is used as an end point. Biochemical follow-up of replacement therapy with thyroxine in primary hypothyroidism therefore requires the use of an ultrasensitive TSH assay in order to detect such suppression. Serum levels of thyroxine or triiodothyronine (T3) during thyroxine therapy are poor indicators of pituitary TSH secretion and are therefore not useful as parameters of adequate thyroxine dosage.
采用超敏促甲状腺激素（TSH）检测法，以确定65例接受甲状腺素（T4）替代治疗的原发性甲状腺功能减退症患者中有多少人的血清TSH受到抑制。13例患者（20%）的TSH水平小于或等于0.1 mIU/l，表明甲状腺素过量。调整剂量后，48例患者的TSH值恢复正常。他们的甲状腺素平均剂量为119微克/24小时，且合适的替代剂量往往随着年龄的增长而降低。甲状腺素替代治疗期间甲状腺激素的血清水平并不能很好地反映血清TSH值。得出的结论是，当以血清TSH受抑制作为终点时，甲状腺素过量的情况很常见。因此，对原发性甲状腺功能减退症患者进行甲状腺素替代治疗的生化随访需要使用超敏TSH检测法，以便检测到这种抑制情况。甲状腺素治疗期间的甲状腺素或三碘甲状腺原氨酸（T3）血清水平并非垂体TSH分泌的良好指标，因此不能用作甲状腺素适当剂量的参数。
