Are we using Thyroid Function Tests Appropriately?

Thyroid function tests are very important for the diagnosis and monitoring of patients with thyroid dysfunction. The guidelines recommend serum thyroid stimulating hormone (TSH) as the single most reliable test to diagnose all common forms of hypothyroidism and hyperthyroidism. The aim of this study was to analyze the ordering pattern for thyroid function tests by physicians and the analysis of results based on the clinical history. The mean age of the patients was 32.5 ± 6.5 years. Majority of samples (87.7% of total) were received from the departments of Medicine and Gynae. Thyroid profiles (47.5%) were ordered more frequently as compared to TSH only (46%). There was no significant difference in the percentage of normal reports for both types of tests. 77.8% of TFT and 76.6% of TSH samples had results within the reference range. The percentage of abnormal results was 13.7% in the patients who were screened for thyroid disorders. There is a need to redefine the case definition for thyroid dysfunction and order the appropriate test in a rational and cost effective manner.     

Deregulation of microRNA expression in thyroid tumors简

MicroRNAs (miRNAs or miRs) are endogenous non-coding RNAs that negatively regulate gene expression by binding to the 3′ non-coding regions of target mRNAs, resulting in their cleavage or blocking their translation. miRNAs may have an impact on cell differentiation, proliferation, and survival, and their deregulation can be inclined to diseases and cancers, including thyroid tumors. The purpose of this review is to summarize the existing findings of deregulated miRNAs in different types of thyroid tumors and to exhibit their potential target genes, especially to demonstrate those involved in tumor invasion and metastasis. In addition, new findings of circulating miRNA expression profiles, single nucleotide polymorphism (SNP) in thyroid tumors, and the correlation of somatic mutations with deregulated miRNA expression in thyroid tumors were all included in this review.     

Metastasis of gastric carcinoma to the thyroid and lung: a case report and review of literature

Cancer metastasis to the thyroid is extremely rare. The more commonly reported primary sites for metastasis to the thyroid are the kidney, breast, lung, colon, esophagus, and uterus. Thyroid metastasis from the stomach has only been reported in three cases. Herein, we report a 71-year-old man presenting with bilateral thyroid multinodular lesions. Bilateral near-total thyroidectomy was performed due to airway compression with related symptoms. Wedge resection of a suspicious pulmonary nodule, detected on CT, was performed for diagnosis. Polypoid lesions in the stomach were examined by trans-scopic biopsy. Poorly differentiated adenocarcinomas with the same histological profiles were noted at these three sites. The immunohistochemical staining for thyroglobulin of these specimens was negative. We conclude that a new thyroid mass appearing in a patient with present or prior malignancies should raise the concern of metastatic disease.     

An audit of total and free thyroxine measurements in screening for hypo and hyperthyroidism in patients using chemiluminescence immunoassay

An audit of 2509 patient specimens analyzed for both total thyroxine (TT4) and free thyroxine (FT4) by the ACS-180 automated chemiluminescence immunoassay analyzer revealed that there were 219 discrepancies (8.7% of the total). A discrepancy was defined as one analyte within its reference range and the other outside. The discrepant results were divided into 4 groups: group A: normal TT4, but decreased FT4, 101 patients (4.0%); group B: increased TT4, normal FT4, 78 patients (3.1%); group C: decreased TT4, normal FT4, 34 patients (1.4%); and group D: normal TT4, increased FT4, 6 patients (0.2%). TSH measurements were available, by a 3^rd generation chemiluminescent assay, in 142 of these patients, and were consistent with the FT4 result in 72 patients, with TT4 in 61 cases and with neither in 9 patients. The clinical diagnosis was investigated in a subgroup of 43 endocrine patients. Thirteen of the 20 endocrine patients in group A were diagnosed as hypothyroid, with a measured serum TSH, in 11 of them, of median 14.6, range 1.2 to 46.2 μlU/ml. Eleven of the 19 endocrine patients in group B were on thyroid replacement, with a measured serum TSH, in 7 of them of <0.01 μlU/ml. The audit of current laboratory practice led to a suggestion to replace the current thyroid function screening strategy of measuring both TT4 and FT4 by the combination of FT4 and TSH. The reasons for the discrepancies and the alternative strategies for screening of thyroid function are discussed.     

早孕妇女甲状腺激素的测定结果分析

探讨人绒毛膜促性腺激素(hCG)是否具有垂体促甲状腺激素(TSH)样作用。方法:应用放射免疫方法(RIA)对65例旱孕妇女hCG与甲状腺激素水平进行测定。结果:早孕妇女Ⅰ组(停经35—50天)3,3’,5’-三碘甲状腺原氨酸(rT_3)水平升高,与正常对照组差异显著(P<0.01);早孕妇女Ⅱ组(停经51—80天)甲状腺素(T_4)、游离甲状腺素(FT_4)、rT_3水平均升高,与正常对照组差异显著(P<0.01);而两组早孕妇女的三碘甲状腺原氨酸(T_3)、游离三碘甲状腺原氨酸(FT_3)水平与正常对照组无明显差异(P>0.05)。结论:hCG具有TSH样作用,早孕妇女甲状腺激素水平升高为hCG促使甲状腺功能增强所致。     

高碘地区和非高碘地区育龄妇女甲状腺功能和血液抗氧化能力的对比研究

目的对比研究高碘地区和非高碘地区育龄妇女的甲状腺功能和血液抗氧化能力。方法测定高碘地区和非高碘地区育龄妇女甲状腺功能指标和血液抗氧化酶活性。结果高碘地区育龄妇女血中总甲状腺素(TT3)明显高于非高碘地区,而游离三碘甲腺原氨酸(FT3)明显低于非高碘地区。高碘地区育龄妇女血中TT3和FT3的异常率高于非高碘地区;高碘地区育龄妇女血中谷胱甘肽过氧化物酶(GSH-Px)和超氧化物酶(SOD)的活性低于非高碘地区。结论高碘地区育龄妇女甲状腺激素水平异常的比率高于非高碘地区,从而有可能增加甲状腺疾病发生的风险;高碘地区育龄妇女血中GSH-Px和SOD的活性均低于非高碘地区,长期摄入高碘有可能使当地育龄妇女抗氧化损伤的能力降低,导致机体的氧化损伤。     

Establishment of Trimester-Specific Reference Intervals of Serum TSH & fT4 in a Pregnant Indian Population at North Kolkata

Reference intervals (RIs) of serum thyroid stimulating hormone (TSH) and free thyroxine (fT₄) were determined in 402 healthy pregnant women by enzyme-linked immunosorbent assay (ELISA) technique after partitioning them into three trimesters. The reference population was chosen from a study population of 610 pregnant females by applying strict inclusion and exclusion criteria. The assays were done using proper quality control measures. RIs were calculated from the central 95 % of the distribution of TSH and fT₄ values located between the lower reference limit of 2.5 percentile and upper reference limit of 97.5 percentile value 0.90 confidence intervals for the upper and lower reference limits were also determined. The reference intervals for TSH were 0.25–3.35 μIU/ml for the first trimester; 0.78–4.96 μIU/ml for the second trimester and 0.89–4.6 μIU/ml for the third trimester. Similarly, the reference intervals for fT₄ for first, second and third trimesters were 0.64–2.0, 0.53–2.12 and 0.64–1.98 ng/dl respectively. The values thus obtained varied from those provided by the kit literature. In comparison to our derived reference intervals, the reference data from kit manufacturer under-diagnosed both subclinical hypo- and hyper-thyroidism within our pregnant reference population.     

A study of thyroid status in hyperemesis gravidarum

Study was undertaken to assess thyroid status in hyperemesis gravidarum. 150 women pregnant with <20 weeks of gestation were selected randomly and out of these 100 women presenting with hyperemesis formed study group while 50 normal pregnant women served as controls. 53% of hyperemetic pregnant women were primigravidae and 82% of pregnant women presented with vomiting at less than 12 weeks of gestation. Statistically significant, 22% of hyperemetic women had increased serum T₃ levels while T₄ levels were increased in 67% of women in study group as compared to 8% and 16% respectively in control group. TSH levels were decreased in 18% of hyperemetic women as compared to 8% in control group with decrease in mean TSH level statistically significant. 22% of hyperemetic women had electrolyte disturbances and 7% were ketonuric. In clinically euthyroid women, biochemically altered thyroid function can attribute to vomiting and its prolongation to second trimester     

Thyroid hormone status in protein energy malnutrition in Indian children

Thyroid hormonal status was measured in 80 malnourished children of different grades (I–IV) of protein energy malnutrition (PEM). Serum levels of tri-iodo thyronine (T₃), thyroxine (T₄) and thyroid stimulating hormone (TSH) were measured by radioimmunoassay. The results were compared with 20 healthy, age and sex matched controls. Levels of T₃ and T₄ were significantly low in PEM cases whereas TSH levels were similar in PEM cases when compared to controls.