Spencer C, Eigen A, Shen D, Duda M, Qualls S, Weiss S, Nicoloff J
Clin Chem. 1987 Aug;33(8):1391-6.
Thyrotropin (TSH) concentrations were measured in 1580 hospitalized patients and 109 normal persons. Using the mean +/- 3 SD limits of the log values for the controls (0.35-6.7 milli-int. units/L), the proportion of abnormal TSH results in the hospitalized patients was 17.2%. TSH was undetectable (less than 0.1 milli-int. unit/L) in 3.1% of patients, suggesting hyperthyroidism, and high (greater than 20 milli-int. units/L) in 1.6%, suggesting hypothyroidism. On follow-up of 329 patients, 62% with abnormal TSH (less than 0.35 or greater than 6.7 milli-int. units/L) and 38% with normal TSH concentrations, only 24% of those with undetectable TSH had thyroid disease: 36% of them were being treated with glucocorticoids and 40% had nonthyroidal illness (NTI). Although half the patients with TSH greater than 20 milli-int. units/L had thyroid disease, 45% of patients had high TSH values associated with NTI. TSH concentrations usually returned towards normal when patients' therapy with glucocorticoids was discontinued or they recovered from NTI. TSH test sensitivity appeared good when the mean +/- 3 SD limits of the reference population were used, i.e., no cases of hyper- or hypothyroidism, as identified by free thyroxin index (FT4I), were missed. However, TSH test specificity was inferior to that of the FT4I test (90.7% vs 92.3%), although specificity could be improved to 97.0% if the wider TSH reference limits of 0.1 to 20 milli-int. units/L were used--limits considered pathological if applied to outpatients. Evidently, different reference intervals for TSH are needed for hospitalized and nonhospitalized patients. We conclude that a "sensitive TSH assay" is not a cost-effective thyroid screening test for hospitalized patients as compared with the FT4I.
对1580例住院患者和109名正常人测定了促甲状腺激素（TSH）浓度。以对照组对数数值的均值±3标准差范围（0.35 - 6.7毫国际单位/升）为标准，住院患者中TSH结果异常的比例为17.2%。3.1%的患者TSH检测不到（低于0.1毫国际单位/升），提示甲状腺功能亢进，1.6%的患者TSH值高（高于20毫国际单位/升），提示甲状腺功能减退。在对329例患者的随访中，TSH异常（低于0.35或高于6.7毫国际单位/升）的患者占62%，TSH浓度正常的患者占38%，TSH检测不到的患者中只有24%患有甲状腺疾病：其中36%正在接受糖皮质激素治疗，40%患有非甲状腺疾病（NTI）。虽然TSH高于20毫国际单位/升的患者中有一半患有甲状腺疾病，但45%的患者TSH值高与NTI有关。当患者停止使用糖皮质激素治疗或从NTI中恢复时，TSH浓度通常会恢复正常。当使用参考人群的均值±3标准差范围时，TSH检测的敏感性似乎良好，即通过游离甲状腺素指数（FT4I）确定的甲状腺功能亢进或减退病例均未漏诊。然而，TSH检测的特异性低于FT4I检测（90.7%对92.3%），不过如果使用0.1至20毫国际单位/升这一更宽的TSH参考范围（该范围应用于门诊患者时被视为病理性范围），特异性可提高到97.0%。显然，住院患者和非住院患者需要不同的TSH参考区间。我们得出结论，与FT4I相比，“敏感TSH检测”对住院患者而言并非具有成本效益的甲状腺筛查检测方法。
