Witherspoon L R, Shuler S E, Garcia M M, Zollinger L A
J Nucl Med. 1980 Jun;21(6):529-39.
Three commercial kit methods for the estimation of free thyroxine (FT4) (Clinical Assays, Corning Medical, Damon Diagnostics) were evaluated. The effects of changes in thyroxine-binding globulin (TBG) and FT4 concentrations in these systems were assessed. Measurements were made in serum samples from hyperthyroid, hypothyroid, and euthyroid patients with different TBG concentrations, and results were correlated with functional thyroid status. The Clinical Assays and Damon Diagnostics assays were found to be essentially independent of binding-protein concentration effects and responded appropriately to changes in FT4 concentration. The method of Corning Medical does not measure FT4 directly but yields an FT4 index calculated from a TBG-dependent T4 uptake and the total T4 concentration. This corning index yields falsely elevated results in patients with marked elevation in TBG concentration.
对三种用于估算游离甲状腺素（FT4）的商业试剂盒方法（临床检测、康宁医疗、达蒙诊断）进行了评估。评估了这些系统中甲状腺素结合球蛋白（TBG）和FT4浓度变化的影响。对不同TBG浓度的甲状腺功能亢进、甲状腺功能减退和甲状腺功能正常患者的血清样本进行了测量，结果与甲状腺功能状态相关。发现临床检测和达蒙诊断检测基本上不受结合蛋白浓度影响，并能对FT4浓度变化做出适当反应。康宁医疗的方法不是直接测量FT4，而是得出一个由依赖TBG的T4摄取量和总T4浓度计算得出的FT4指数。在TBG浓度显著升高的患者中，这个康宁指数会得出错误升高的结果。
