Bayer M F, Kriss J P, McDougall I R
J Nucl Med. 1985 Nov;26(11):1248-56.
A two-site immunoradiometric assay for serum thyrotropin (TSH) was modified to improve the analytical sensitivity. The sensitivity achieved (detection limit, approximately 0.1 microU/ml; lower limit of quantitative measurement, approximately 0.4 microU/ml) was comparable to that of the best competitive binding research assays, yet this assay can be performed routinely. Serum TSH was 1.82 +/- 0.69 (mean +/- s.d.) (range 0.4-3.4 microU/ml) in healthy individuals and 1.83 +/- 0.90 microU/ml (range 0.7-3.7 microU/ml) in patients with nonthyroidal disorders. By contrast, 97% of clinically hyperthyroid patients (Graves' disease, toxic nodular goiter) with high serum free T4 (FT4) and T3 had suppressed serum TSH values, i.e., less than 0.3 microU/ml. Among patients with euthyroid Graves' ophthalmopathy or nontoxic goiter those clinically suspected of mild hyperthyroidism had TSH values less than 0.3 microU/ml, while those judged euthyroid had normal values. A large proportion of thyroid patients on antithyroid drugs (poorly to well-controlled) had suppressed TSH. Of Graves' patients in remission (normal FT4 and T3), 75% had normal TSH, but individual levels changed significantly over time, suggesting that a progressive decline in TSH may be useful in predicting recurrences. In hypothyroid patients taking L-T4, serum TSH was subnormal in patients with elevated FT4, but TSH was also low in six patients clinically suspected to be thyrotoxic despite normal FT4 and T3 and in 32% of asymptomatic patients with normal thyroid hormone levels. Conversely, 23% of thyroid cancer patients who had undergone thyroidectomy were taking insufficient L-T4 to completely suppress TSH secretion. In 25 individuals who underwent thyrotropin releasing hormone (TRH) stimulation tests, the baseline serum TSH value correlated well with the peak serum TSH value post-TRH (r = 0.85). We conclude that sensitive TSH measurements could establish or confirm the diagnosis of hyperthyroidism in equivocal cases, replace most TRH-stimulation tests and be of value in optimizing L-T4 suppression therapy for thyroid cancer patients post-thyroidectomy.
一种用于血清促甲状腺激素（TSH）的双位点免疫放射分析方法被改进以提高分析灵敏度。所达到的灵敏度（检测限约为0.1微单位/毫升；定量测量下限约为0.4微单位/毫升）与最佳的竞争性结合研究分析方法相当，但该分析方法可常规进行。健康个体的血清TSH为1.82±0.69（平均值±标准差）（范围为0.4 - 3.4微单位/毫升），非甲状腺疾病患者的血清TSH为1.83±0.90微单位/毫升（范围为0.7 - 3.7微单位/毫升）。相比之下，97%临床甲状腺功能亢进患者（格雷夫斯病、毒性结节性甲状腺肿）血清游离T4（FT4）和T3升高，其血清TSH值被抑制，即低于0.3微单位/毫升。在患有甲状腺功能正常的格雷夫斯眼病或非毒性甲状腺肿的患者中，临床怀疑有轻度甲状腺功能亢进的患者TSH值低于0.3微单位/毫升，而被判定甲状腺功能正常的患者TSH值正常。很大一部分服用抗甲状腺药物（控制不佳至控制良好）的甲状腺患者TSH被抑制。在格雷夫斯病缓解期（FT4和T3正常）的患者中，75%的患者TSH正常，但个体水平随时间有显著变化，这表明TSH的逐渐下降可能有助于预测复发。在服用左甲状腺素（L - T4）的甲状腺功能减退患者中，FT4升高的患者血清TSH低于正常水平，但在6例临床怀疑甲状腺毒症但FT4和T3正常的患者以及32%甲状腺激素水平正常的无症状患者中TSH也较低。相反，23%接受甲状腺切除术的甲状腺癌患者服用的L - T4不足以完全抑制TSH分泌。在25例接受促甲状腺激素释放激素（TRH）刺激试验的个体中，基线血清TSH值与TRH刺激后血清TSH峰值相关性良好（r = 0.85）。我们得出结论，敏感的TSH测量可以在可疑病例中确立或证实甲状腺功能亢进的诊断，取代大多数TRH刺激试验，并对优化甲状腺癌患者甲状腺切除术后的L - T4抑制治疗有价值。
