Milinković Neda, Ignjatović Svetlana, Žarković Miloš, Jovičić Snežana, Radosavljević Branimir, Singh Sandra, Majkić-Singh Nada
Center for Medical Biochemistry, Clinical Center of Serbia , Belgrade , Serbia.
Scand J Clin Lab Invest. 2014 Aug;74(5):378-84. doi: 10.3109/00365513.2014.898324. Epub 2014 Mar 31.
Defining adequate reference limits (RLs) for thyroid hormones is an important task for support monitoring and the treatment of subclinical thyroid disease. We determined whether there are age-related RLs for thyroid parameters in male and female outpatients free of overt thyroid disease.
We analyzed 22,860 results (11,440 male and 11,420 female outpatients above the age of 18) for thyrotropin (TSH), free thyroxine (fT4) and total triiodothyronine (T3) that were stored in our laboratory information system between 2008 and 2011. We calculated the 2.5th and 97.5th centiles for the analyzed thyroid parameters.
Our results indicate higher TSH levels with ageing, with a significant difference (p < 0.05) between the 97.5th centiles for males and females older than 70 (5.07 mIU/L and 4.10 mIU/L), but also a significant difference between male and female fT4 from 31 to 40 and from 41 to 50 years old (18.4 vs 14.9 pmol/L and 19.0 vs 15.9 pmol/L, p < 0.05), respectively. Overall indirect estimates of the 97.5th centiles for TSH for males and females were not significantly different and were below the generally recommended upper limit (4.01 mIU/L and 4.20 mIU/L, respectively). In addition, we found no statistically significant change in mean T3 values in the analyzed population.
This cross-sectional study indicates change in TSH and fT4 levels with ageing and gender-related upper limits. This suggests that by using indirect estimation a laboratory could provide clinicians with more accurate gender- and age-specific RLs for thyroid parameters.
确定甲状腺激素的适当参考值范围（RLs）是支持亚临床甲状腺疾病监测和治疗的一项重要任务。我们确定了无明显甲状腺疾病的男性和女性门诊患者的甲状腺参数是否存在与年龄相关的参考值范围。
我们分析了2008年至2011年存储在我们实验室信息系统中的22860份促甲状腺激素（TSH）、游离甲状腺素（fT4）和总三碘甲状腺原氨酸（T3）检测结果（11440名男性和11420名18岁以上女性门诊患者）。我们计算了所分析甲状腺参数的第2.5百分位数和第97.5百分位数。
我们的结果表明，TSH水平随年龄增长而升高，70岁以上男性和女性的第97.5百分位数之间存在显著差异（p<0.05）（分别为5.07 mIU/L和4.10 mIU/L），但31至40岁以及41至50岁的男性和女性fT4之间也存在显著差异（分别为18.4对14.9 pmol/L和19.0对15.9 pmol/L，p<0.05）。总体而言，男性和女性TSH第97.5百分位数的间接估计值无显著差异，且低于一般推荐的上限（分别为4.01 mIU/L和4.20 mIU/L）。此外，我们发现所分析人群的平均T3值无统计学显著变化。
这项横断面研究表明TSH和fT4水平随年龄和性别相关上限而变化。这表明通过间接估计，实验室可以为临床医生提供更准确的甲状腺参数性别和年龄特异性参考值范围。
