Analytical Performance and Clinical Utility of Thyroid Function Tests

在一项多机构合作研究中，我们评估了甲状腺激素抑制治疗良性多结节性甲状腺疾病的潜在临床应用。本研究采用我们先前开发的定量研究综合方法进行。该方法包括对相关临床研究和专家意见的文献进行系统回顾，对选定的介入研究进行荟萃分析，对NIH内分泌学从业人员进行调查，以确定良性甲状腺多结节性疾病患者的治疗方案，对NIH接受左旋甲状腺素抑制治疗的良性甲状腺多结节性疾病患者进行实践验证，并应用Hill？评估甲状腺抑制治疗与良性结节消退之间的因果关系的标准。与我们早期观察甲状腺抑制治疗对良性孤立性甲状腺结节的影响类似，我们发现一小部分良性多结节性甲状腺疾病患者对这种药物治疗有反应，结节大小在临床上显着减小。因此，在没有左旋甲状腺素给药禁忌症的良性甲状腺多结节疾病患者中，该疗法的初步试验是有必要的。在另一项研究中，我们评估了一例肾病综合征患者需要增加左甲状腺素替代治疗剂量以达到甲状腺功能正常状态的病例。临床表现类似于“不适当的”促甲状腺激素（TSH）分泌综合征。我们分析了不同采血管对不同非同位素方法测量游离甲状腺素（FT4）、游离碘甲状腺原氨酸（FT3）和促甲状腺激素（TSH）的影响。我们观察到只有一种类型的收集管在一些试验中有显著的临床效果。然而，研究结果表明，在将这些试管用于甲状腺功能检测之前，对其进行常规评估是有必要的。

In a multi-institute collaborative study, we assessed the potential clinical utility of thyroid hormone suppression therapy on benign multinodular thyroid disease. The study was performed using our previously developed method of quantitative research synthesis. This approach involved systematic review of the literature for relevant clinical studies and expert opinions, meta-analysis of selected interventional studies, surveys of NIH endocrinology practitioners for therapeutic decisions in hypothetic patients with benign multinodular thyroid disease, practice validation in NIH patients treated with levothyroxine suppression for benign multinodular thyroid disease, and application of Hill?s criteria to assess causality between thyroid suppression therapy and regression of benign nodules. Similar to our earlier observation for the effect of thyroid suppression therapy on benign solitary thyroid nodules, we found that a subset of patients with benign multinodular thyroid disease responded to this medical therapy with clinically significant reduction in nodule size. Consequently, an initial trial of this therapy is warranted in patients with benign multinodular thyroid disease in the absence of contraindication(s) to levothyroxine administration. In another study, we evaluated a case in which increased doses of levothyroxine replacement therapy were required to achieve euthyroid status in a patient with nephrotic syndrome. The clinical picture thus mimicked an "inappropriate" thyroid-stimulating hormone (TSH) secretion syndrome.We analyzed the effect of various blood collection tubes on the measurements of free thyroxine (FT4), free iodothyronine (FT3), and TSH (thyroid-stimulating hormone or thyrotropin) with different nonisotopic methods. We observed clinically significant effects only with one type of collection tube on some assays. Nevertheless, the findings indicate that routine evaluation of these tubes is warranted before their use for thyroid function testing.