Viera Anthony J
Department of Family Practice, Naval Hospital Jacksonville, FL 32214, USA.
Fam Med. 2003 Jun;35(6):408-10.
Despite improved thyroid function testing assays, appropriate use of these commonly ordered tests to detect thyroid dysfunction remains controversial. This study determined if a normal sensitive thyroid stimulating hormone (sTSH) test alone is sufficient to rule out thyroid dysfunction in outpatients.
This was a retrospective analysis of initial sTSH and free thyroxine index (FT4) tests ordered during a 26-month period. Test results were classified as concordant if both the sTSH and FT4 indicated the same findings (ie, euthyroid, hyperthyroid, or hypothyroid). The results were classified as discordant if the sTSH and FT4 did not indicate the same findings.
There were 1,392 paired sTSH and FT4 results. Of 1,340 results classified as concordant (96.2%), 1,187 specimens were consistent with euthyroidism, 41 with hyperthyroidism, and 112 with hypothyroidism. Of the remaining 52 (3.8%) discordant results, 47 met the definition of subclinical thyroid dysfunction. Excluding these 47 results yielded a concordance rate of 99.6%. Of the 1,192 normal sTSH results, FT4 was low in two and high in three. If FT4 tests had not been ordered on the 1,192 specimens with normal sTSH levels, the savings over the study period would have been more than dollars 3,360.
If the sTSH is normal, the likelihood of an abnormal FT4 is very small. sTSH alone is adequate to screen outpatients for thyroid dysfunction. Limiting FT4 tests to those with abnormal sTSH results will result in cost savings.
尽管甲状腺功能检测方法有所改进，但合理运用这些常用检测来诊断甲状腺功能障碍仍存在争议。本研究旨在确定仅通过一次正常的敏感促甲状腺激素（sTSH）检测是否足以排除门诊患者的甲状腺功能障碍。
这是一项对26个月期间所做的初始sTSH和游离甲状腺素指数（FT4）检测进行的回顾性分析。如果sTSH和FT4检测结果显示相同结果（即甲状腺功能正常、甲状腺功能亢进或甲状腺功能减退），则检测结果被分类为一致。如果sTSH和FT4检测结果未显示相同结果，则检测结果被分类为不一致。
共有1392对sTSH和FT4检测结果。在1340例被分类为一致的结果中（96.2%），1187份标本符合甲状腺功能正常，41份符合甲状腺功能亢进，112份符合甲状腺功能减退。在其余52例（3.8%）不一致的结果中，47例符合亚临床甲状腺功能障碍的定义。排除这47例结果后，一致率为99.6%。在1192例sTSH结果正常的病例中，FT4偏低的有2例，偏高的有3例。如果未对1192例sTSH水平正常的标本进行FT4检测，那么在研究期间节省的费用将超过3360美元。
如果sTSH正常，FT4异常的可能性非常小。仅sTSH就足以筛查门诊患者的甲状腺功能障碍。将FT4检测限于sTSH结果异常的患者可节省费用。
