Waud J M, Chan D W, Drew H M, Oropeza M J, Sucupira M S, Scheinin B, Garrison G M, Mayo M, Taylor E, Stem J
Clin Chem. 1983 Nov;29(11):1908-11.
We have investigated the clinical utility of two direct radioimmunoassays for free thyroxin, an enzyme-inhibition immunoassay, and a direct measurement of thyroxin-binding globulin (TBG) by radioassay. All assay methods correctly identified greater than or equal to 90% of euthyroid, hyperthyroid, and hypothyroid patients who had normal TBG concentrations. In patients with altered TBG concentrations, none of the assays correctly classified all categories of patients. However, the direct assays of free thyroxin concentrations were able to classify correctly more patients with altered TBG concentrations than did the free thyroxin index methods. The free thyroxin index methods evaluated may be acceptable for routine use, if the concentration of thyroxin and the measurement of TBG capacity are reported along with the index value. Patients with altered TBG concentrations included a group of euthyroid pregnant patients. Significant decreases in free thyroxin in the third trimester were detected by all the assays studied. For patients in the first and second trimester, the mean free thyroxin concentration measured varied with the assay method.
我们研究了两种游离甲状腺素直接放射免疫测定法、一种酶抑制免疫测定法以及通过放射测定法直接测量甲状腺素结合球蛋白（TBG）的临床实用性。所有检测方法都能正确识别出TBG浓度正常的甲状腺功能正常、甲状腺功能亢进和甲状腺功能减退患者中90%及以上的病例。在TBG浓度改变的患者中，没有一种检测方法能正确分类所有类型的患者。然而，游离甲状腺素浓度的直接检测方法比游离甲状腺素指数方法能正确分类更多TBG浓度改变的患者。如果在报告游离甲状腺素指数值的同时，还报告甲状腺素浓度和TBG容量的测量值，那么所评估的游离甲状腺素指数方法可用于常规检测。TBG浓度改变的患者包括一组甲状腺功能正常的孕妇。所有研究的检测方法都检测到妊娠晚期游离甲状腺素显著降低。对于妊娠早期和中期的患者，所测游离甲状腺素的平均浓度因检测方法而异。
