Wood D G, Cyrus J, Samols E
J Nucl Med. 1980 May;21(5):432-5.
Of 128 euthyroid hospitalized patients with nonthyroidal illnesses (NTI), 33% had a low total thyroxine (T4). Forty-three percent of the latter patients had a low free thyroxine index. In euthyroid patients with NTI, free T4 was, with rare exceptions, within the range for well euthyroid controls. The free T4, as determined by two different radioimmunoassays, was diagnostically low in 34 of 37 hypothyroid patients without NTI. However, in hypothyroid patients with NTI, the free T4 determination was less informative. Only four of ten patients had a low free T4 by the Corning test, and none of ten were low by the Clinical Assays test. Our data suggest that patients with NTI frequently have low T4 and low FT4I, despite being euthyroid. Low free T4 strongly suggests hypothyroidism, but normal free T4 in patients with NTI does not exclude hypothyroidism.
在128例患有非甲状腺疾病（NTI）的甲状腺功能正常的住院患者中，33%的患者总甲状腺素（T4）水平较低。在这些T4水平较低的患者中，43%的患者游离甲状腺素指数较低。在患有NTI的甲状腺功能正常的患者中，除极少数例外，游离T4处于甲状腺功能正常的健康对照者的范围内。通过两种不同的放射免疫测定法测定，在37例无NTI的甲状腺功能减退患者中，有34例的游离T4在诊断上较低。然而，在患有NTI的甲状腺功能减退患者中，游离T4测定的信息量较少。通过康宁试验，10例患者中只有4例游离T4较低，而通过临床分析试验，10例患者中无一例游离T4较低。我们的数据表明，患有NTI的患者尽管甲状腺功能正常，但经常出现T4和游离甲状腺素指数（FT4I）较低的情况。游离T4水平低强烈提示甲状腺功能减退，但NTI患者游离T4正常并不能排除甲状腺功能减退。
