Chen Li-Min, Chen Yen-Chun, Hsiao Hui-Pin, Chen Bai-Hsiun, Chao Mei-Chyn
Department of Pediatrics, E-Da Hospital, Kaohsiung, Taiwan; Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
Division of Genetics, Endocrinology and Metabolism, Department of Pediatrics, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.
Kaohsiung J Med Sci. 2014 Aug;30(8):383-9. doi: 10.1016/j.kjms.2014.04.005. Epub 2014 May 28.
The thyrotropin-releasing hormone (TRH) test is useful for differentiating central and primary hypothyroidism, and is also valuable for diagnosing hypothyroidism. The threshold of the TRH test is usually set at 10-40 mIU/L. However, some experts are of the opinion that the TRH test has a limited role in evaluating hypothyroidism because of the clinical application of the new-generation thyroid-stimulating hormone (TSH) assay. We reviewed a case series to analyze the clinical use of the TRH test in the re-evaluation of congenital hypothyroidism. In total, data on 228 children with eutopic thyroid glands and neonatal hyperthyrotropinemia under levothyroxine replacement were collected. Basal TSH levels were measured and the TRH test was performed at the age of 3 years for re-evaluation of congenital hypothyroidism, and statistical analysis was performed. All of the patients were followed up to avoid over- or under-treatment. At the age of 3 years, 31.6% of the patients still had hypothyroidism. There was no significant difference between basal TSH level and TRH test in the diagnosis of hypothyroidism (p = 0.23). The negative predictive value of the basal TSH level was 100%, however, the positive predictive value was only 43.6%. When the TSH level was near the upper limit of the normal range (4.5-8.5 mIU/L), the TRH test result had a better correlation with hypothyroidism than the basal TSH level (p = 0.03). The threshold of the TRH test set at 60 mIU/L had the greatest area under the curve, with a negative predictive value of 95.2% and a positive predictive value of 80.2%. Neonatal hyperthyrotropinemia was a risk factor for hypothyroidism. We suggest that the TRH test should be administered in children with a basal TSH value near the upper limit of the normal range, and the threshold of the TRH test should be set at 60 mIU/L.
促甲状腺激素释放激素（TRH）试验有助于鉴别中枢性和原发性甲状腺功能减退症，对诊断甲状腺功能减退症也有价值。TRH试验的阈值通常设定为10 - 40 mIU/L。然而，一些专家认为，由于新一代促甲状腺激素（TSH）检测方法的临床应用，TRH试验在评估甲状腺功能减退症方面的作用有限。我们回顾了一系列病例，以分析TRH试验在先天性甲状腺功能减退症重新评估中的临床应用。总共收集了228例甲状腺位置正常且在左甲状腺素替代治疗下新生儿促甲状腺激素血症患儿的数据。测量基础TSH水平，并在3岁时进行TRH试验以重新评估先天性甲状腺功能减退症，并进行统计学分析。对所有患者进行随访以避免治疗过度或不足。3岁时，31.6%的患者仍患有甲状腺功能减退症。基础TSH水平和TRH试验在诊断甲状腺功能减退症方面无显著差异（p = 0.23）。基础TSH水平的阴性预测值为100%，然而，阳性预测值仅为43.6%。当TSH水平接近正常范围上限（4.5 - 8.5 mIU/L）时，TRH试验结果与甲状腺功能减退症的相关性比基础TSH水平更好（p = 0.03）。将TRH试验阈值设定为60 mIU/L时曲线下面积最大，阴性预测值为95.2%，阳性预测值为80.2%。新生儿促甲状腺激素血症是甲状腺功能减退症的一个危险因素。我们建议，基础TSH值接近正常范围上限的儿童应进行TRH试验，且TRH试验的阈值应设定为60 mIU/L。
