PURPOSE Recently published papers have demonstrated that particularly in untreated individuals, clinical parameters more often associate with thyroid hormone, particularly free thyroxine (FT4), levels than with thyrotropin (TSH) levels. Clinical and research assessments of the thyroid state of peripheral tissues would therefore be more precise if they were based on FT4 levels rather than on TSH levels. In this paper we describe implications of, and opportunities provided by, this discovery. CONCLUSIONS The FT4 level may be the best single test of thyroid function. The addition of free triiodothyronine (FT3) and TSH levels would further enhance test sensitivity and distinguish primary from secondary thyroid dysfunction respectively. There are opportunities to reconsider testing algorithms. Additional potential thyroidology research subjects include the peripheral differences between circulating FT4 and FT3 action, and outcomes in patients on thyroid replacement therapy in terms of thyroid hormone levels. Previously performed negative studies of therapy for subclinical thyroid dysfunction could be repeated using thyroid hormone levels rather than TSH levels for subject selection and the monitoring of treatment. Studies of outcomes in older individuals with treatment of high normal FT4 levels, and pregnant women with borderline high or low FT4 levels would appear to be the most likely to show positive results. There are fresh indications to critically re-analyse the physiological rationale for the current preference for TSH levels in the assessment of the thyroid state of the peripheral tissues. There may be opportunities to apply these research principles to analogous parameters in other endocrine systems.

中文翻译：

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甲状腺检测范式从促甲状腺素到甲状腺激素的转变——临床医学和研究的未来方向和机遇。

目的 最近发表的论文表明，特别是在未经治疗的个体中，临床参数更常与甲状腺激素相关，尤其是游离甲状腺素 (FT4) 水平，而不是促甲状腺激素 (TSH) 水平。因此，如果基于 FT4 水平而不是 TSH 水平，对外周组织甲状腺状态的临床和研究评估会更加精确。在本文中，我们描述了这一发现的含义和提供的机会。结论 FT4水平可能是甲状腺功能的最佳单项检测。添加游离三碘甲状腺原氨酸 (FT3) 和 TSH 水平将进一步提高检测灵敏度并分别区分原发性和继发性甲状腺功能障碍。有机会重新考虑测试算法。其他潜在的甲状腺学研究主题包括循环 FT4 和 FT3 作用之间的外周差异，以及甲状腺替代治疗患者在甲状腺激素水平方面的结果。以前对亚临床甲状腺功能障碍的治疗进行的阴性研究可以使用甲状腺激素水平而不是 TSH 水平重复进行受试者选择和治疗监测。对接受高正常 FT4 水平治疗的老年人和具有临界高或低 FT4 水平的孕妇结果的研究似乎最有可能显示出积极的结果。有新的迹象可以批判性地重新分析当前在评估外周组织甲状腺状态时偏爱 TSH 水平的生理学原理。