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Objectives Hormone measurements using automated immunoassays (IAs) can be affected by the sample matrix. Liquid chromatography tandem-mass spectrometry (LC-MS/MS) is less affected by these matrix effects. In clinical laboratories, testosterone, cortisol and, free thyroxine (FT4) are often measured using IAs. Renal failure alters serum composition in blood samples from people undergoing hemodialysis (HDp) and have, therefore, a complex serum constitution compared to healthy controls (HC). The goal of this study was to investigate the accuracy of testosterone, cortisol, and FT4 measurements in samples of HDp and to get more insight in the interfering factors. Methods Thirty serum samples from HDp and HC were collected to measure testosterone, cortisol, and FT4 using a well standardized isotope dilution (ID)-LC-MS/MS method and 5 commercially available automated IAs (Alinity, Atellica, Cobas, Lumipulse, UniCel DXI). Method comparisons between LC-MS/MS and IAs were performed using both HDp and HC samples. Results Average bias from the LC-MS/MS was for testosterone, cortisol, and FT4 immunoassays respectively up to 92, 7–47 and 16–27% more in HDp than in HC samples and was IA dependent. FT4 IA results were falsely decreased in HDp samples, whereas cortisol and testosterone concentrations in females were predominantly falsely increased. Correlation coefficients between LC-MS/MS and IA results were lower in HDp compared to HC samples. Conclusions Several IAs for testosterone (in women), cortisol, and FT4 are less reliable in the altered serum matrix of samples of HDp than in HC. Medical and laboratory specialists should be aware of these pitfalls in this specific population.

Introduction In our hospital, physicians noticed high free thyroxine (fT4) concentrations without complete suppression of thyroid-stimulating hormone (TSH) in blood samples of patients at the outpatient clinic, which appeared to occur more often following the introduction of a new fT4 immunoassay. This discordance may be explained by incorrect reference intervals, analytical issues, or patient-related factors. We aimed to establish the contribution of the possible factors involved. Methods Reference intervals of both fT4 immunoassays were re-evaluated using blood samples of healthy volunteers and the new immunoassay’s performance was assessed using internal quality controls and external quality rounds. The frequency of discordant fT4 and TSH pairings obtained from laboratory requests were retrospectively analysed using a Delfia (n = 3174) and Cobas cohort (n = 3408). Last, a literature search assessed whether the time of blood draw and the time of levothyroxine (L-T4) ingestion may contribute to higher fT4 concentrations in L-T4 users. Results The original reference intervals of both fT4 immunoassays were confirmed and no evidence for analytical problems was found. The Delfia (n = 176, 5.5%) and Cobas cohorts (n = 295, 8.7%) showed comparable frequencies of discordance. Interestingly, 72–81% of the discordant results belonged to L-T4 users. Literature indicated the time of blood withdrawal of L-T4 users and, therefore, the time of L-T4 intake as possible explanations. Conclusions High fT4 without suppressed TSH concentrations can mainly be explained by L-T4 intake. Physicians and laboratory specialists should be aware of this phenomenon to avoid questioning the assay’s performance or unnecessarily adapting the L-T4 dose in patients.

Огляд літератури присвячений вторинному гіпотиреозу — рідкісній патології, при діагностиці та лікуванні якої виникає низка питань і труднощів. Основними причинами вторинного гіпотиреозу у дорослих є пухлини гіпоталамо-гіпофізарної ділянки, а також стан після оперативного і променевого впливу на цю ділянку. Гормонально активні та неактивні макроаденоми гіпофіза є причиною розвитку набутого вторинного гіпотиреозу в більше ніж 50 % випадків. При променевій терапії пухлин головного мозку розвиток вторинного гіпотиреозу можливий через декілька років після проведеного лікування. Як і при первинному гіпотиреозі, клінічні прояви вторинного гіпотиреозу неспецифічні. Діагностика та лікування цього захворювання найчастіше ускладнюються його поєднанням з недостатністю інших тропних гормонів. Основу діагностики вторинного гіпотиреозу становлять анамнестичні дані і лабораторні показники — одночасне визначення концентрації тиреотропного гормона і вільного тироксину. Вміст вільного тироксину також використовують як основний маркер адекватності дози левотироксину при лікуванні вторинного гіпотиреозу. Результати нещодавно опублікованих праць дозволяють оптимізувати замісну терапію при вторинному гіпотиреозі, однак дотепер залишається невивченим питання використання додаткових біохімічних маркерів для оцінки адекватності замісної терапії.

Background: Human chorionic gonadotropin (hCG) is a marker of placental function, which also stimulates the maternal thyroid gland. Maternal thyroid function can be associated with the pathophysiology of gestational diabetes mellitus (GDM). We aimed to study whether there is an association of hCG concentrations in early pregnancy with GDM and whether it is mediated through maternal thyroid hormones. Methods: This study included 18,683 pregnant women presenting at a tertiary hospital in Shanghai, China, between January 2015 and December 2016. GDM was diagnosed using a 2-hour, 75-g, oral glucose tolerance test (OGTT) according to the American Diabetes Association guidelines. Multivariable logistic or linear regression models were used to identify associations, adjusting for maternal age, education level, family history of diabetes, parity, fetal sex, thyroperoxidase antibody (TPOAb) status, and prepregnancy body-mass index. Results: Higher hCG concentrations were associated with a lower plasma glucose level during the OGTT, but not with fasting plasma glucose or hemoglobin A1c concentrations tested during early pregnancy. hCG in early pregnancy was negatively associated with GDM risk (p = 0.027). Mediation analysis identified that an estimated 21.4% of the association of hCG-associated GDM risk was mediated through changes in free thyroxine (fT4) concentrations (p < 0.05). In the sensitivity analysis restricted to TPOAb-positive women, hCG was not associated with GDM (p = 0.452). Conclusions: Higher hCG levels in early pregnancy are associated with a lower risk of GDM. Maternal fT4 may act as an important mediator in this association.

Thyroid dysfunctions are among the most common endocrine disorders and accurate biochem ical testing is needed to confirm or rule out a diagnosis. Notably, true hyperthyroidism and hypothyroidism in the setting of a normal thyroid- stimulating hormone level are highly unlikely, making the assessment of free thyroxine (FT4) inappropriate in most new cases. However, FT4 measurement is integral in both the diagnosis and management of relevant central dysfunctions (central hypothyroidism and central hyperthyroidism) as well as for monitoring therapy in hyper thyroid patients treated with anti- thyroid drugs or radioiodine. In such settings, accurate FT4 quantification is required. Global standardization will improve the comparability of the results across laboratories and allow the development of common clinical decision limits in evidence based guidelines. The International Federation of Clinical Chemistry and Laboratory Medicine Committee for Standardization of Thyroid Function Tests has undertaken FT4 immunoassay method comparison and recalibration studies and developed a reference measurement proced ure that is currently being validated. However, technical and implementation challenges, includ ing the establishment of different clinical decision limits for distinct patient groups, still remain. Accordingly, different assays and reference values cannot be interchanged. Two-way communica tion between the laboratory and clinical specialists is pivotal to properly select a reliable FT4 assay, establish reference intervals, investigate discordant results, and monitor the analytical and clinical performance of the method over time.

Optimal Vitamin D (VitD) status and thyroid function are essential for pregnant women. This study aimed to explore associations between dynamic VitD status and thyroid function parameters in each trimester and throughout the pregnancy period. Information on all 8828 eligible participants was extracted from the Peking University Retrospective Birth Cohort in Tongzhou. Dynamic VitD status was represented as a combination of deficiency/sufficiency in the first and second trimesters. Thyroid function was assessed in three trimesters. The associations between VitD and thyroid function were assessed by multiple linear regression and generalized estimating equation models in each trimester and throughout the pregnancy period, respectively. The results indicated that both free thyroxine (fT4; β = 0.004; 95%CI: 0.003, 0.006; p < 0.001) and free triiodothyronine (fT3; β = 0.009; 95%CI: 0.004, 0.015; p = 0.001) had positive associations with VitD status in the first trimester. A VitD status that was sufficient in the first trimester and deficient in the second trimester had a lower TSH (β = −0.370; 95%CI: −0.710, −0.031; p = 0.033) compared with the group with sufficient VitD for both first and second trimesters. In conclusion, the associations between VitD and thyroid parameters existed throughout the pregnancy. Maintaining an adequate concentration of VitD is critical to support optimal thyroid function during pregnancy.

Purpose: The aim of this study was to evaluate the relationship between thyroid hormone levels and clinical outcomes in preterm, small for gestational age (SGA) infants.Materials and Methods: The premature newborns (gestational age of ≤30 weeks) were divided into two groups as SGA and non-SGA. Thyroid stimulating hormone (TSH) and free thyroxine (fT4) levels, the frequency of congenital hypothyroidism (CH), demographic and clinical characteristics, morbidity and mortality rate were compared between the groups.Results: A total of 430 premature newborns, 72 in the SGA group and 358 in the non-SGA group were included. The frequency of CH, morbidity, demographic and clinical characteristics were similar between two groups. The mortality rate was higher in SGA (36.1%) than in non-SGA group (13.6%). Serum fT4 level was lower in SGA group (1.04±0.30 ng/dl) compared to the non-SGA group (1.24±0.33 ng/dl). The serum TSH level was higher in SGA group (9.91 ± 5.6 uIU/L) than in non-SGA group (6.6 ± 5.2 uIU/L).Conclusion: The frequency of thyroid dysfunction was higher in preterm SGA infants compared to non-SGA, which was due to transiently high TSH and low fT4 concentrations. Therefore, thyroid function tests should be monitored periodically in preterm and SGA infants., Amaç: Bu çalışmada erken doğmuş, gebelik yaşına göre küçük (SGA) bebeklerde tiroid hormon düzeyleri ile klinik sonuçlar arasındaki ilişkiyi değerlendirilmesi amaçlanmıştır.Gereç ve Yöntem: Prematüre yenidoğanlar (gebelik yaşı ≤30 hafta) SGA olan ve olmayan olarak iki gruba ayrıldı. Gruplar arasında tiroid uyarıcı hormon (TSH) ve serbest tiroksin (sT4) düzeyleri, konjenital hipotiroidizm (KH) sıklığı, demografik ve klinik özellikler, morbidite ve mortalite oranları karşılaştırıldı.Bulgular: SGA grubunda 72 ve SGA olmayan grupta 358 olmak üzere toplam 430 prematüre yenidoğan dahil edildi. KH sıklığı, morbidite, demografik ve klinik özellikler iki grup arasında benzerdi. Mortalite oranı SGA'da (%36,1) SGA olmayan gruptan (%13,6) daha yüksekti. Serum sT4 düzeyi SGA grubunda (1,04±0,30 ng/dl) SGA olmayan gruba göre (1,24±0,33 ng/dl) daha düşüktü. Serum TSH düzeyi SGA grubunda (9,91 ± 5,6 uIU/L), SGA olmayan gruptan (6,6 ± 5,2 uIU/L) daha yüksekti.Sonuç: Tiroid disfonksiyonu sıklığı, geçici olarak yüksek TSH ve düşük fT4 konsantrasyonlarına bağlı olarak, preterm SGA bebeklerde SGA olmayanlara kıyasla daha yüksekti. Bu nedenle erken doğmuş ve SGA bebeklerde tiroid fonksiyon testleri periyodik olarak izlenmelidir.

Context Clinical hypothyroidism (CH) and subclinical hypothyroidism (SCH) have been linked to various metabolic comorbidities but the underlying metabolic alterations remain unclear. Metabolomics may provide metabolic insights into the pathophysiology of hypothyroidism. Objective We explored metabolic alterations in SCH and CH and identify potential metabolite biomarkers for the discrimination of SCH and CH from euthyroid individuals. Methods Plasma samples from a cohort of 126 human subjects, including 45 patients with CH, 41 patients with SCH, and 40 euthyroid controls, were analyzed by high-resolution mass spectrometry–based metabolomics. Data were processed by multivariate principal components analysis and orthogonal partial least squares discriminant analysis. Correlation analysis was performed by a Multivariate Linear Regression analysis. Unbiased Variable selection in R algorithm and 3 machine learning models were utilized to develop prediction models based on potential metabolite biomarkers. Results The plasma metabolomic patterns in SCH and CH groups were significantly different from those of control groups, while metabolite alterations between SCH and CH groups were dramatically similar. Pathway enrichment analysis found that SCH and CH had a significant impact on primary bile acid biosynthesis, steroid hormone biosynthesis, lysine degradation, tryptophan metabolism, and purine metabolism. Significant associations for 65 metabolites were found with levels of thyrotropin, free thyroxine, thyroid peroxidase antibody, or thyroglobulin antibody. We successfully selected and validated 17 metabolic biomarkers to differentiate 3 groups. Conclusion SCH and CH have significantly altered metabolic patterns associated with hypothyroidism, and metabolomics coupled with machine learning algorithms can be used to develop diagnostic models based on selected metabolites.

Background Contrary to patients with hypothyroidism after radioiodine (HRI) or after thyroidectomy (HTh), patients with central hypothyroidism (CH) cannot rely on thyrotropin (TSH) level to guide their treatment with L-thyroxine (L-T4). Consequently, they are at constant risk of under- or overtreatment. We aimed to establish the adequacy of L-T4 treatment in patients with CH in our cohort. Methods Consecutive patients with CH on L-T4 treatment were compared with patients adequately treated for HRI or HTh. Levels of free thyroxine (fT4) and free triiodothyronine (fT3) were evaluated and the fT4/fT3 ratio was calculated. Results Forty patients with CH, 136 patients with HRI and 43 patients with HTh were included in this study. Patients with HRI were significantly younger than patients with HTh and CH (p Conclusions Patients with CH have lower fT4 levels and lower fT4/fT3 ratios than patients adequately treated for HRI or HTh. The cause for this difference may be the unreliable TSH levels in patients with CH.

Made available in DSpace on 2022-05-01T07:58:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-09-01 In humans and pets, magnetic resonance imaging (MRI) provides important adjunctive anatomic information about the thyroid and its adjacent structures. To the best of our knowledge, however, no studies have been reported regarding the use of MRI for thyroid evaluation in horses. The aim of this study was to obtain qualitative and quantitative parameters of healthy thyroid gland in adult horses by MRI. Eleven horses were submitted to thyroid MRI evaluation. The healthy thyroid of these animals was ensured by normal examinations performed before (free thyroxine and ultrasound) and after (cytology) to MRI. It was concluded that the dorsal spin-echo T1-weighted, fast spin-echo T2-weighted, sagittal STIR and a three-dimensional T1-weighted gradient echo were the sequences that best characterized the thyroid lobes. Qualitatively, there was a significant variation in the elliptical format of some lobes considering the sagittal plane, which oscillated between rounded and flattened conformation. Excellent reproducibility of the quantitative thyroid parameters obtained was verified. The thyroid gland total volume mean of observers was 14.31 cm3 (±0.69). In relation with comparisons between quantitative parameters of left and right lobes, only differences regarding their respective lengths were observed. Thus, we can infer that the difference in some thyroid lobes format can be explained by the significant variation identified between left and right lobes lengths. Department of Animal Reproduction and Veterinary Radiology São Paulo State University (UNESP) Department of Veterinary Surgery and Anesthesiology São Paulo State University (UNESP) Department of Veterinary Clinic São Paulo State University (UNESP) Department of Animal Production São Paulo State University (UNESP) Department of Animal Reproduction and Veterinary Radiology São Paulo State University (UNESP) Department of Veterinary Surgery and Anesthesiology São Paulo State University (UNESP) Department of Veterinary Clinic São Paulo State University (UNESP) Department of Animal Production São Paulo State University (UNESP)

Screening for hypo- or hyperthyroidism in adults is generally done by measuring the serum thyrotropin (thyroid-stimulating hormone, TSH) concentration. This is an efficient approach in case of suspected acquired thyroid disease. However, in infants and children, congenital hypothalamus-pituitary-thyroid (HPT) axis disorders also need to be considered, including primary and central congenital hypothyroidism, and even rarer thyroid hormone receptor and transporter defects. In primary congenital hypothyroidism, TSH will be elevated, but in the other congenital HPT axis disorders, TSH is usually within the normal range. Free thyroxine (FT4) assessment is essential for the diagnosis in these conditions.Conclusion: Here we discuss a number of rare congenital HPT axis disorders in which TSH is normal, but FT4 is low, and provide a clinical algorithm to distinguish between these disorders. What is Known:• A single thyroid-stimulating hormone (TSH) measurement is an appropriate screening method for primary hypothyroidism.• For central hypothyroidism and rare thyroid hormone receptor and transporter defects a free thyroxine (FT4) measurement is essential for the diagnosis because TSH is usually normal. What is New:• Here we present a new problem-oriented clinical algorithm including a diagnostic flow-chart for low FT4 and normal TSH in infants and children.

Objectives The Canadian Laboratory Initiative on Pediatric Reference Intervals (CALIPER) has developed an extensive database of reference intervals (RIs) for several biomarkers on various analytical systems. In this study, pediatric RIs were verified for key immunoassays on the Abbott Alinity system based on the analysis of healthy children samples and comparison to comprehensive RIs previously established for Abbott ARCHITECT assays. Methods Analytical performance of Alinity immunoassays was first assessed. Subsequently, 100 serum samples from healthy children recruited with informed consent were analyzed for 16 Alinity immunoassays. The percentage of test results falling within published CALIPER ARCHITECT reference and confidence limits was determined. If ≥ 90% of test results fell within the confidence limits, they were considered verified based on CLSI guidelines. If Results Of the 16 immunoassays assessed, 13 met the criteria for verification with test results from ≥ 90% of healthy serum samples falling within the published ARCHITECT confidence limits. New CALIPER RIs were established for free thyroxine and prolactin on the Alinity system. Estradiol required special considerations in early life. Conclusions Our data demonstrate excellent concordance between ARCHITECT and Alinity immunoassays, as well as the robustness of previously established CALIPER RIs for most immunoassays, eliminating the need for de novo RI studies for most parameters. Availability of pediatric RIs for immunoassays on the Alinity system will assist clinical laboratories using this new platform and contribute to improved clinical decision-making.

Background: Melasma has been suspected to be linked with levels of thyroid hormone. There is no study that explains the association between thyroid hormone level with melasma severity. Objective: This study aims to find the discrepancies in the levels of thyroid hormone in varying severity of melasma by using two different measurement techniques. Methods: Subjects were chosen consecutively from the dermatology clinic at RSUPN Dr. Cipto Mangunkusomo hospital. Forty-eight patients participated in this study were categorized into mild melasma and moderate-severe melasma based on modified melasma area and severity index (mMASI) and Janus II measurement. Results: Statistically, mMASI measurement showed no significant association between varying melasma severity with levels of thyroid stimulating hormone and free T4 (FT4), P 0.375 and P 0.208, respectively. The Janus II examination using polarized light modality has a weak positive correlation with the serum FT4 level (r=0.3; P 0.039). Weak correlation was also found between the two measurement strategies, Janus II and mMASI (r= 0.314; P 0.03). Conclusion: There are no significant differences observed in levels of thyroid hormone between subjects with varying degrees of melasma severity.

Objectives National Baseline Health Research 2013 showed that there were 706,757 (0.4%) hyperthyroid patients in Indonesia. Hyperthyroidism is characterized by abnormal thyroid stimulating immunoglobulin (TSI) which causes low TSH and high FT4 levels. Hyperthyroid patients have a decrease of serum iron levels due to acute phase reactions of hyperthyroidism. This study aimed to analyze the correlation between dietary iron intake and serum iron with TSH and FT4 levels in adult hyperthyroid patients. Methods This study was conducted in February–July 2020 at the Clinic of Magelang Health Research and Development Center. Sampling of this cross sectional study was based on inclusion criteria in order to obtain 50 adult hyperthyroid patients. Dietary iron intake was collected with 2 × 24 h dietary recall, serum iron was measured with colorimetric analysis, the levels of TSH and FT4 were measured by ELISA. The collected data were analyzed using Spearman correlation and multivariate linear regression with 95% confidence level. Results Deficiencies of dietary iron intake was found in 20 hyperthyroid patients (40%). Low serum iron levels were found in 10 hyperthyroid patients (20%). Spearman correlation analysis showed that dietary iron intake had a negative correlation with TSH (r=−0.294; p0.05), while serum iron didn’t associated with both TSH (r=0.110; p>0.05) and FT4 (r=0.142; p>0.05). Furthermore, regression analysis showed that dietary iron intake, serum iron, phytate, and thyrozol intake correlate with TSH levels (R square=0.193; p0.05). Conclusions Intake and serum of iron didn’t correlate with TSH and FT4 levels in adult hyperthyroid patients.

The improvement in accuracy of in vitro diagnosis has always been the focus of early screening of thyroid dysfunction. We constructed a microfluidic chip based on a polystyrene polymer substrate. Total triiodothyronine (TT3), total thyroxine (TT4), free triiodothyronine (FT3), free thyroxine (FT4), and thyrotropin (TSH) in human whole blood samples were analysed by fluorescence immunoassay to evaluate thyroid function. The results indicate that the microfluidic chip shows a good linear relationship in the detection of TT3, TT4, FT3, FT4, and TSH standards, and the correlation coefficient (r) is not less than 0.9900. In addition, the chip also has strong anti-interference (RSD% ≤ 5%) and good repeatability (CV ≤ 8%), and its inter-batch differences are small (CV ≤ 15%). The results of practical application in clinical thyroid function measurement indicated its high accuracy (r ≥ 0.9900). It provides a new method for the determination of thyroid function and lays a foundation for subsequent clinical application.

The objective of this study was to compare the levels of prolactin, FSH, LH, E2, TSH, FT4 and BMI between infertile Saudi women with high prolactin and fertile Saudi women with normal prolactin. The study individuals were divided into two groups; infertile Saudi women with high prolactin (Group 1) and fertile Saudi women with normal prolactin (Group 2). This study used the ARCHITECT i1000SR immunoassay analyzer for the assessment of all serum hormones. The prolactin in Group 1 was higher than in the Group 2. The FSH and LH values were similar in both groups. The TSH in Group 1 was higher than in the Group 2. The FT4 values were similar in both groups. The BMI in both groups was greater than 25 (all patients were in over weight category). In Group 1, 40% women were over weight and in Group 2, 39 % women were over weight. The rate of failed cycles in group 1 was higher than in Group 2, also cases of PCOS in Group 1 were more than in the Group 2. The rate of positive pregnancy in Group 1 is lower than in the Group 2. The results of this study demonstrated that increased levels of prolactin and TSH are among the causes of infertility in Saudi women.

Background Recombinant human growth hormone (rhGH) was approved for the therapy of pediatric patients with growth hormone deficiency (GHD) by the Food and Drug Administration (FDA) of the United States in 1985. This study aims to evaluate the effects of rhGH therapy on thyroid function in pediatric patients with GHD. Methods A total of 55 pediatric patients, who had been diagnosed with GHD and received rhGH therapy for 6-24 months, and who could regularly come to our hospital for outpatient visits from May 1, 2014 to April 30, 2017, were selected for the study. All of the patients were treated for at least six months, among which 44 patients were treated for 12 months, and 32 patients were treated for 18 months, and 16 patients were treated for 24 months. Results (I) During the course of the rhGH therapy, none of the patients had a free thyroxine (FT4) level lower than the normal lower limit. (II) The FT4 level decreased during the course of the therapy, when compared to the level at baseline, and the difference was statistically significant after 24 months of therapy. In the puberty group, the FT4 level had significantly decreased by the 12th month of therapy, when compared to the baseline, but there was no significant change in the FT4 and thyroid-stimulating hormone (TSH) levels at the remaining observation time points of treatment. Conclusions Growth hormone (GH) replacement therapy may affect the metabolism of the thyroid hormone in pediatric patients with GHD. During the course of treatment, the changes in thyroid function in pediatric patients with GHD should be regularly monitored in order to identify any abnormal thyroid function in its early stages.

The aim of this study was to investigate the thyroid functions in children receiving levetiracetam or valproate monotherapy. We retrospectively reviewed the records of children with controlled epilepsy receiving valproic acid (VPA group) or levetiracetam monotherapy (LEV group) for at least 6 months. Free thyroxine 4 levels (fT4) and thyroid stimulating hormone (TSH) levels were compared between VPA group, LEV group, and age- and gender-matched healthy children (control group). A total of 190 children were included in the study: 63 were in the VPA, 60 in the LEV, and 67 in the control group. Although there was no significant difference regarding average fT4 levels, higher TSH levels were found in the VPA group when compared with the LEV and control groups (p

BACKGROUND Thyroid hormone is known to regulate metabolisms which are an integral part of normal growth and development. It affects key metabolisms involved in energy storage and expenditure. We wanted to study the correlation of thyroid function test with metabolic markers. METHODS After appropriate clearance from Human Institutional Ethics Committee and proper permission from author of article by Dr Sindhu et al, the secondary, blinded data was adopted for this study. This is an observational, cross-sectional retrospective study. Anthropometric measurements were taken, and lipid and thyroid profile were analysed in overnight fasting sample. As per our inclusion and exclusion criteria 120 of 253 subjects included in primary study were recruited in our study. Statistical analysis was done in Microsoft Excel 2007 and SPSS software version 16.0. ATP III criteria were used as a benchmark for metabolic syndrome markers. RESULTS Our study suggests that prevalence of subclinical hypothyroidism was higher in young South Indian women and it significantly correlated with the markers of metabolic syndrome like BMI, waist circumference, Low Density Lipoprotein (LDL) and systolic blood pressure. TSH values strongly correlated with BMI and LDL values. FT4 values correlated well with LDL. CONCLUSIONS High TSH and lower thyroxine values in blood can be a marker associated with metabolic syndrome. Our study suggests routine screening for thyroid status and lipid profile in young females to categorize them as high risk for cardiovascular mortality and morbidity along with anthropometric measurements. The study can be continued by long term follow up of the study subjects and correlation of these study subjects into mid or old age can give significant information of their cardiac status at that age. Counseling on appropriate diet and lifestyle modification may be beneficial for young people categorized as high risk to reduce the cardiovascular mortality later in life. KEYWORDS Thyroid Stimulating Hormone, Free Thyroxine, BMI, Lipid Profile

Yong Guo, Chun-Yan Wu, Yu-Hong Deng, Jie-Ling Wu Department of Children’s Health Care, Guangdong Women and Children Hospital, Guangzhou Medical University, Guangzhou 511400, People’s Republic of ChinaCorrespondence: Jie-Ling WuDepartment of Children’s Health Care, Guangdong Women and Children Hospital, Guangzhou Medical University, Guangzhou 511400, People’s Republic of ChinaTel +86 2039151521Email jieling3861@163.comPurpose: Vitamin D deficiency has been linked to overt thyroid diseases. Data on the effects of vitamin D status on thyroid function in children are less examined. The goal of the present study was to explore the association between serum 25-hydroxyvitamin D [25(OH)D] levels and thyroid function parameters in early childhood.Patients and Methods: This was a cross-sectional study involving record-linkage of children’s data of routine health check-ups for promoting early childhood development at Guangdong Women and Children’s Hospital; 2869 children aged 6– 24 months were included from January 2015 to May 2017. Serum 25(OH)D, thyroid stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxine (FT4) levels were measured using the electrochemiluminescence immunoassay.Results: The study population had a mean serum 25(OH)D level of 79.7 ± 28.1 nmol/L and 12.5% vitamin D deficiency and 36.0% insufficiency rates. The rates of thyroid dysfunctions detected were 2.9% hypothyroidism, 4.2% subclinical hypothyroidism, 0.9% hyperthyroidism, and 1.7% subclinical hyperthyroidism among the previously healthy children aged 6 to 24 months. Serum 25(OH)D levels had no significant correlation with TSH (r = 0.022, P = 0.236), FT3 (r = 0.014, P = 0.440) and FT4 (r = − 0.059, P = 0.056) levels. No significant difference in the levels of thyroid hormones was found between the different quartiles of 25(OH)D level. Vitamin D deficiency [25(OH)D < 50 nmol/L] was associated with hypothyroidism (adjusted odds ratio = 2.16, 95% confidence interval: 1.18– 3.94) but not with subclinical hypothyroidism, hyperthyroidism, and subclinical hyperthyroidism.Conclusion: Vitamin D deficiency is slightly associated with hypothyroidism. No associations were found between serum 25(OH)D levels and thyroid-related measures (TSH, FT3, and FT4) in previously healthy children aged 6– 24 months.Keywords: thyroid stimulating hormone, free triiodothyronine, free thyroxine

Background-aim Measurement of serum thyrotropin is currently the recommended test for the screening of thyroid dysfunction, while serum free thyroxine is kept as a reflex test. In our laboratory, the strategy followed in adult individuals from Primary Care includes a ‘safety margin’ for requests with a thyrotropin ≤1.0 or ≥4.0 mIU/L (normal: 0.35–4.95 mIU/L). Our aim was to optimize the thyrotropin cut-off values for the addition of free thyroxine and, based on these cut-offs, to retrospectively analyze avoidable free thyroxine measurements and possible adverse clinical consequences. Methods Retrospective observational study performed in a tertiary care hospital between 2013 and 2018. We considered all laboratory requests for screening of thyroid dysfunction (TD) in adult patients from Primary Care. Requests from patients with a previous diagnosis of thyroid disease or pregnant women were excluded. Different receiver operating characteristic (ROC) curves were performed and the obtained thyrotropin cut-off values were compared. Economic savings were assessed considering the current cost of free thyroxin assays in our laboratory. Results From a total of 554,529 TD protocols included, 119,504 requests had free thyroxine added. From the ROC curve that enables ≥95% of abnormal free thyroxine results to be detected, the thyrotropin values obtained were ≥4.58 mIU/L and ≤0.94 mIU/L. These thyrotropin cut-off values would lead to a saving of 22.7% of annual free thyroxine measurements without adverse clinical consequences. Discussion Setting optimized thyrotropin cutoffs for reflex testing of free thyroxine would reduce the need for this test. Clinical laboratories need to offer not only true results, but also become the cornerstone in the optimization of resources.

OBJECTIVE: Our goal was to evaluate the analytical performance of the novel immunoassay platform and to compare the agreement between thyroid-stimulating hormone (TSH) and FT4 results, obtained by novel and currently used platform. MATERIALS AND METHODS: Both immunoassay platforms, current Immulite 2000 and novel Maglumi 800, are based on chemiluminecsence immunoassay method. Analytical performance was evaluated by the use of serum pools and commercial quality control samples. The comparison study was carried out with 80 serum samples. Obtained results were analyzed by descriptive statistics, Mann–Whitney U-test, and Paired t-test. Method comparison was performed with Passing-Bablok regression analysis and Bland-Altman plots. RESULTS: TSH Maglumi 800 showed better within-run precision for both concentration ranges (1.7–2.8 CV%) in comparison to Immulite 2000 (4.4–5.7 CV%). FT4 Maglumi 800 imprecision was higher compared with Immulite 2000 FT4 in both within-run (3.5–3.9 CV% vs. 4.9–6.6 CV%) and between-run (3.6–4.2 CV% vs. 4.6–5.9 CV%) tests. Mann–Whitney U-test for TSH revealed non-significant difference between data (p = 0.9011). Regression analysis showed no systematic (intercept = 0.01), nor proportional (slope = 0.9781) differences. Non-significant bias was observed in Bland-Altman Plots. For FT4, we found significant differences between methods using paired t-test (t39 = 10.5, p < 0.0001) and significant difference (p = 0.00745) with Mann–Whitney U-test. Bland-Altman plot revealed 22.8% average bias. CONCLUSION: TSH evaluation showed good precision and close agreement between Maglumi 800 and Immulite 2000 methods, which assures transferability of results. However, FT4 performance evaluation revealed higher imprecision of Maglumi 800 platform and significant differences of test results.

Objectives The first objective was to assess correlation between free thyroxine (fT4) measurements by equilibrium dialysis (fT4ED; Antech Diagnostics) and a chemiluminescent enzyme immunoassay (fT4CEIA; IMMULITE 2000 Veterinary Free T4 [Siemens Healthcare Diagnostics Products]) in hyperthyroid, otherwise healthy, cats before (T0), and 1 month (T1) and 11–23 months (T2) after radioactive iodine (131I) therapy. The second objective was to determine correlation between thyroid status based on fT4 (by both techniques) and the gold standard, thyroid scintigraphy. Methods Thyroid status, including thyroid-stimulating hormone (TSH), total thyroxine (TT4) and fT4 serum concentrations, were assessed in 45 client-owned hyperthyroid cats before (T0), and 1 month (T1) and 11–23 months (T2) after 131I therapy. fT4 was determined by a chemiluminescent enzyme immunoassay (CEIA) and equilibrium dialysis (ED). Quantitative thyroid scintigraphy (with sodium 99m-Tc-pertechnetate) was performed at T2. Results Spearman correlation between fT4CEIA and fT4ED was 0.81, 0.88 and 0.79 at T0, T1 and T2, respectively. fT4CEIA was consistently lower than fT4ED, with a median difference of −5.4 pmol/l ( P Conclusions and relevance Good correlation exists between both assays at T1 and T2, but a significant systematic difference is noted at both time points. This could be an indication for reconsideration of the current RI, although further studies are warranted for assessing test accuracy (in otherwise healthy cats and cats with non-thyroidal illness). At this time, routine use of fT4CEIA after 131I therapy is not advised in feline patients.

Disorders of thyroid function are among the commonest referrals to endocrinology. While interpretation of thyroid function testing is usually straightforward, accurate interpretation becomes significantly more challenging when the parameters do not behave as would be expected in normal negative feedback. In such cases, uncertainty regarding further investigation and management arises. An important abnormal pattern encountered in clinical practice is that of high normal or raised free thyroxine (fT4) with inappropriately non-suppressed or elevated thyroid-stimulating hormone (TSH). In this short review using two clinical vignettes, we examine the diagnostic approach in such cases. A diagnostic algorithm is proposed to ensure that a definitive diagnosis is reached in these challenging cases.

Xiaomin Nie,* Yun Shen,* Xiaojing Ma, Yiting Xu, Yufei Wang, Jian Zhou, Yuqian Bao Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital; Shanghai Clinical Center for Diabetes; Shanghai Key Clinical Center for Metabolic Disease; Shanghai Diabetes Institute; Shanghai Key Laboratory of Diabetes Mellitus, Shanghai 200233, People’s Republic of China*These authors contributed equally to this workCorrespondence: Xiaojing Ma; Yuqian BaoDepartment of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai Clinical Center for Diabetes; Shanghai Key Clinical Center for Metabolic Disease; Shanghai Diabetes Institute; Shanghai Key Laboratory of Diabetes Mellitus, 600 Yishan Road, Shanghai 200233, People’s Republic of ChinaTel +86-21-64369181Fax +86-21-64368031Email maxiaojing@sjtu.edu.cn; yqbao@sjtu.edu.cnPurpose: Although overt thyroid dysfunction has been found to influence the level of glycated albumin (GA), the associations between thyroid hormones and GA in individuals with euthyroidism and subclinical hypothyroidism (SHypo) are still unknown. The present study aimed to investigate whether thyroid hormones were related to GA in euthyroid and SHypo individuals.Methods: We recruited 685 euthyroid and 103 SHypo subjects with normal weight from communities in Shanghai. Electrochemiluminescence immunoassay was used to detect the serum levels of free triiodothyronine (FT3), free thyroxine (FT4) and thyroid stimulating hormone. GA was detected by the enzymatic method. Glycated hemoglobin (HbA1c) was detected by high-performance liquid chromatography.Results: Among the 788 subjects (age range 31– 81 years old), 307 were men and 481 were women. In the Spearman correlation analysis and multiple stepwise regression analysis, FT3 was negatively correlated with both GA and GA/HbA1c in euthyroid subjects (all P < 0.05). The values of GA and GA/HbA1c were reduced by approximately 0.30 and 0.05, respectively, for each 0.50 pmol/L increment in FT3. In SHypo subjects, FT4 was negatively associated with both GA and GA/HbA1c (all P < 0.05). The values of GA and GA/HbA1c were reduced by approximately 0.23 and 0.03, respectively, for each 1.00 pmol/L increment in FT4.Conclusion: In euthyroid and SHypo subjects, more attention should be paid to the potential effects of individual differences in thyroid hormones on GA.Keywords: glycated albumin, glycated hemoglobin, free triiodothyronine, free thyroxine

Xiaomin Nie,* Yun Shen,* Xiaojing Ma, Yiting Xu, Yufei Wang, Jian Zhou, Yuqian Bao Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital; Shanghai Clinical Center for Diabetes; Shanghai Key Clinical Center for Metabolic Disease; Shanghai Diabetes Institute; Shanghai Key Laboratory of Diabetes Mellitus, Shanghai 200233, People’s Republic of China*These authors contributed equally to this workCorrespondence: Xiaojing Ma; Yuqian BaoDepartment of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai Clinical Center for Diabetes; Shanghai Key Clinical Center for Metabolic Disease; Shanghai Diabetes Institute; Shanghai Key Laboratory of Diabetes Mellitus, 600 Yishan Road, Shanghai 200233, People’s Republic of ChinaTel +86-21-64369181Fax +86-21-64368031Email maxiaojing@sjtu.edu.cn; yqbao@sjtu.edu.cnPurpose: Although overt thyroid dysfunction has been found to influence the level of glycated albumin (GA), the associations between thyroid hormones and GA in individuals with euthyroidism and subclinical hypothyroidism (SHypo) are still unknown. The present study aimed to investigate whether thyroid hormones were related to GA in euthyroid and SHypo individuals.Methods: We recruited 685 euthyroid and 103 SHypo subjects with normal weight from communities in Shanghai. Electrochemiluminescence immunoassay was used to detect the serum levels of free triiodothyronine (FT3), free thyroxine (FT4) and thyroid stimulating hormone. GA was detected by the enzymatic method. Glycated hemoglobin (HbA1c) was detected by high-performance liquid chromatography.Results: Among the 788 subjects (age range 31– 81 years old), 307 were men and 481 were women. In the Spearman correlation analysis and multiple stepwise regression analysis, FT3 was negatively correlated with both GA and GA/HbA1c in euthyroid subjects (all P < 0.05). The values of GA and GA/HbA1c were reduced by approximately 0.30 and 0.05, respectively, for each 0.50 pmol/L increment in FT3. In SHypo subjects, FT4 was negatively associated with both GA and GA/HbA1c (all P < 0.05). The values of GA and GA/HbA1c were reduced by approximately 0.23 and 0.03, respectively, for each 1.00 pmol/L increment in FT4.Conclusion: In euthyroid and SHypo subjects, more attention should be paid to the potential effects of individual differences in thyroid hormones on GA.Keywords: glycated albumin, glycated hemoglobin, free triiodothyronine, free thyroxine

Background: Euthyroid individuals with familial dysalbuminemic hyperthyroxinemia (FDH) have often falsely elevated serum free thyroxine (fT4) concentrations determined by different automated immunoassays. Methods: We measured serum fT4 using direct dialysis coupled with tandem mass spectrometry (fT4 DDMS) in individuals with the common albumin gene mutation (ALB R218H) from 14 FDH families and compared them with results obtained by direct immunometric assay (fT4 DIMM) and free thyroxine index (fT4I). Results: While all 14 individuals with FDH had elevated total serum T4, the fT4 measured by DIMM was elevated in 12, by fT4I in 5, and by DDMS in 1. Conclusion: The latter method greatly reduced the discordance of fT4 results relative to thyrotropin in FDH.

Introduction: Multisystem inflammatory syndrome in children (MIS-C) associated with COVID-19 is defined as the presence of documented fever, inflammation, and at least two signs of multisystem involvement and lack of an alternative microbial diagnosis in children who have recent or current SARS-CoV-2 infection or exposure. In this study, we evaluated thyroid function tests in pediatric cases with MIS-C in order to understand how the hypothalamus-pituitary-thyroid axis is affected and to examine the relationship between disease severity and thyroid functions. Material and methods: This case-control study was conducted in our clinic between January 2021 and September 2021. The patient group consisted of 36 MIS-C cases, the control group included 72 healthy children. Demographic features, clinical findings, inflammatory markers, thyroid function tests, and thyroid antibody levels of MIS-C cases were recorded. Thyroid function tests were recorded in the healthy control group. Results: When MIS-C and healthy control groups were compared in terms of thyroid hormones, free triiodothyronine (FT3) level was lower in MIS-C cases, while free thyroxine (FT4) level was found to be lower in the healthy group (p=

Objective Thyroid hormone measurements are often performed in pregnant women, as hypo- and hyperthyroidism during pregnancy can severely affect the fetus. Serum free thyroxine (fT4) measurements are well known for their analytical challenges, due to low serum concentrations and the subtle equilibrium between free and bound T4 (to thyroid-binding globulin (TBG), transthyretin and albumin). Pregnant women have high TBG concentrations due to an increase in human chorionic gonadotropin (hCG) and estrogen and lower albumin concentrations which change the equilibrium and may affect the validity of fT4 measurements in their samples. As accurate serum fT4 measurements in pregnant women are important for the long-term health of the fetus, we aimed to evaluate the accuracy of several fT4 immunoassays in the serum of pregnant women. Methods FT4 was measured in healthy controls and pregnant women using a candidate-reference method (LC-MS/MS) and five commercially available automated immunoassays (Alinity (Abbott), Atellica (Siemens), Cobas (Roche), Lumipulse (Fujirebio) and UniCel DXI (Beckman Coulter)). Method comparisons (Bland Altman plots and Passing and Bablok analyses) were performed. Results Serum samples from both healthy controls (n = 30) and pregnant women (n = 30; mean gestational age, 24.8 weeks) were collected. The fT4 immunoassays deviated +7 to +29% more from the LC-MS/MS in serum samples of pregnant women than healthy controls (falsely high). Conclusions Our results indicate that immunoassays overestimate fT4 in pregnant women, which might lead to an overestimation of thyroid status. Physicians and laboratory specialists should be aware of this phenomenon to avoid drawing false conclusions about thyroid function in pregnant women.

Background Factors causing progression from nonalcoholic fatty liver to nonalcoholic steatohepatitis (NASH) and liver cirrhosis remain relatively unknown. We aimed to evaluate the power and effectiveness of the free triiodothyronine (FT3)-to-free thyroxine (FT4) ratio to predict non-alcoholic fatty liver disease (NAFLD)/liver fibrosis and NASH cirrhosis severity. Methods Patients (n = 436) with NASH-associated liver cirrhosis (n = 68), patients with liver biopsy-proven NAFLD (n = 226), or healthy participants (n = 142) were enrolled between January 2010 and January 2020. The aspartate aminotransferase-to-thrombocyte ratio (APRI), NAFLD fibrosis score, albumin–bilirubin score (ALBI), aspartate aminotransferase (AST)-to-alanine aminotransferase (ALT) ratio, FT3-to-FT4 ratio, and Fibrosis-4 (FIB-4) were calculated and evaluated. Results All parameters were significantly higher in NASH cirrhosis than in the healthy group. Body mass index, ALT, fasting insulin, homeostatic model assessment for insulin resistance, and triglyceride levels were significantly higher in liver biopsy-proven NAFLD than in the healthy group. The APRI, NAFLD fibrosis score, ALBI, AST-to-ALT ratio, FT3-to-FT4 ratio, and FIB-4 were significantly higher in the NASH cirrhosis group than in the healthy group. In patients with biopsy-proven NAFLD, the FT3-to-FT4 ratio was significantly lower than in the healthy group. Conclusion The FT3-to-FT4 ratio is an effective and useful indicator to predict NAFLD/liver fibrosis and NASH cirrhosis severity.

Background Previous studies have reported a negative relationship between thyroid-stimulating hormone (TSH) and renal function in euthyroid individuals, but others have found that higher free thyroxine (FT4) was associated with an increased risk of chronic kidney disease. This study was designed to analyze the relationship between thyroid and renal function from a new perspective of sensitivity to thyroid hormone. Methods This retrospective study included 2831 euthyroid individuals who underwent a health examination at the First Hospital of China Medical University between January 2017 and December 2018. Parametric Thyroid Feedback Quantile-based Index (PTFQIFT4), TSH index (TSHI), thyrotroph T4 resistance index (TT4RI), free triiodothyronine to FT4 ratio (FT3/FT4), the secretory capacity of the thyroid gland (SPINA-GT) and the sum activity of peripheral deiodinases (SPINA-GD) were calculated. We also innovated the TT3RI and PTFQIFT3 indices based on FT3 and TSH. Renal function was assessed by estimated glomerular filtration rate (eGFR) CKD-EPI and creatinine-cystatin C-KDIGO equations. Results After adjustment of basic characteristics and comorbidities, linear regression showed that eGFR CKD-EPI was positively associated with FT3/FT4 (β = 23.31), and inversely correlated to PTFQI FT4 (β= −2.69) (both p

A critical part of diagnosing thyroid disorders is the laboratory evaluation performed through blood testing. A reliable and accurate diagnosis is necessary in order to select the proper treatment options for thyroid disorder patients and help to increase workflow and efficiency. This research was carried out because of increased late diagnosis of thyroid disease in patients suffering from various thyroid disorders. The estimation of free thyroxine, fT 4 , and free triodothyronine, fT 3 was done and used as an index for the differential assessment of thyroid function. A total number of nine hundred and seven (907) patients were diagnosed of various thyroid dysfunctions from the subjects that attended the various hospitals/clinics in the city of Port Harcourt, Rivers State, Nigeria, between the months of February, 2010 to April, 2013. The method of enzyme linked immuno sorbent assay (ELISA) was used in carrying out the study. Out of the 907 patients, 532 of them, representing 58.65% were females while 375 of the patients representing 41.35% were males. From the result analysis, 55.46% of the patients diagnosed of primary hyperthroidism had elevated serum levels of both total and free T 3 , T 4 with low TSH values, while 3.09% of the hyperthyroid cases had normal total T 4 and T 3 but elevated values of fT 4 and fT 3 . 0.88% of the patients with hypothyroidism had normal total T 4 and T 3 , but with low serum levels of fT 4 and fT 3 and was diagnosed so clinically. Triiodothyronine (T 3 ) toxicosis with elevated fT 3 and normal fT 4 serum levels were found in 9.81% of the patients. Non thyroidal illness cases had low serum fT 4 in 9.26% of the patients. Two (about 0.22%) of the patients that were diagnosed of TSH Secreting tumours had an elevated serum fT 4 level in addition to high serum TSH levels. This study showed that fT 3 and fT 4 is actually an index in the differential diagnosis of thyroid diseases. Keywords : Hyperthyroidism, Hypothyroidism, Toxicosis, Non –Thyroidal, Hormone, Thyroxine, Triidothyronine.

We describe a case of severe hyperthyroidism with high free thyroxine and C‐reactive protein levels, wherein thyroid function rapidly improved without treatment. In a similar case, conservative management with imaging follow‐up can be considered.

Clinical interpretation of thyroid labs is usually straightforward. However, there are rare instances when the atypical profile of thyroid labs warrants systematic investigation to determine the underlying cause. We report the case of a 90-year-old Caucasian male with a chronic history of atrial fibrillation with chronic pacemaker dependence who presented with significantly elevated free thyroxine level (>7.77 ng/dL) but normal thyroid-stimulating hormone level (2.15 µIU/mL). After ruling out pituitary tumors and artifactual errors due to lab interference, the diagnosis of thyroid hormone resistance was made.

Background Accumulated evidence has indicated that a high‐normal FT4 level is an independent risk factor for the clinical progression of AF. However, the association between elevated FT4 concentration within the normal range and AF recurrence after cryoballoon ablation in China is unknown. Methods This retrospective and observational study included 453 AF patients who underwent cryoballoon ablation from January 2016 to August 2018. Patients were classified into quartiles based on preprocedural serum FT4 concentration. The clinical characteristics of the patients and the long‐term rate of AF recurrence after ablation were assessed. Results After a mean follow‐up period of 17.4 ± 9.0 months, 91 (20.1%) patients suffered from AF recurrence. The AF recurrence rate by FT4 quartile was 17.7%, 19.0%, 21.4%, and 22.3% for participants with FT4 in quartile 1, 2, 3, and 4, respectively (p

Despite the need for precise measurement of thyroid hormones levels for disease detection and monitoring, the importance of sampling time for the accuracy of widely used assays is unclear. In this study, the effects of the time of day on thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxine (FT4) levels were retrospectively evaluated using data obtained from the Laboratory Information System of Peking Union Medical College Hospital. TSH concentrations were significantly lower, and FT4 and FT3 concentrations were higher in males than in females (all

Background: Serum human chorionic gonadotrophin (hCG) is higher in twin than that in singleton pregnancies. As hCG stimulates the thyroid to produce more free thyroxine (FT4), which may lead to decreased thyroid-stimulating hormone (TSH) levels, the reference ranges of thyroid-related indicators may differ between singleton and twin pregnancies in the first trimester. This study aimed to establish reference ranges for thyroid-related indicators in early twin pregnancies and to compare them with singleton pregnancies. Methods: Data of 820 twin-pregnant women were extracted from the established database of all pregnant women who delivered at Peking University First Hospital from October 2013 to May 2018; 160 who met National Academy of Clinical Biochemistry criteria were included to establish TSH and FT4 reference ranges. We screened 480 (3:1 paired) women with singleton pregnancies from the same database as controls. The Mann-Whitney test for TSH and FT4 levels was applied for comparisons between singleton and twin pregnancies. Results: First-trimester reference ranges (4–12 gestational weeks) for twin pregnancies were: TSH 0.69 (0.01–3.35) mIU/L and FT4 16.38 (12.45–23.34) pmol/L. Median TSH was significantly lower at 7 to 12 gestational weeks than that at 4 to 6 gestational weeks (0.62 vs. 0.96 mIU/L, Z = -1.964, P = 0.049); FT4 was not significantly different between the two groups. Compared to singleton pregnancies, median TSH was significantly lower (0.69 vs. 1.27 mIU/L, Z = -6.538, P = 0.000), and FT4 was significantly higher (16.38 vs. 14.85 pmol/L, Z = -7.399, P = 0.000) in twin pregnancies in the first trimester. Conclusions: Specific reference ranges for thyroid-related indicators for twin pregnancies are needed to avoid a misdiagnosis of thyroid dysfunction. Moreover, establishment of separate reference ranges for 4 to 6 and 7 to 12 gestational weeks in twin pregnancies may be considered. Key words: Twin pregnancy; Reference ranges; Thyroid-stimulating hormone; Free thyroxine

info:eu-repo/semantics/published

To determine an appropriate cut-off of capillary Thyroid stimulating hormone (TSH) for congenital hypothyroidism. Cross-sectional. 174,000 neonates born in different hospitals of Delhi, India, from November 2014 to October 2016. Correlation between initial and repeat capillary TSH level and subsequent venous free thyroxine (fT4) level. 102 newborns with initial/repeat capillary TSH level of ≥20 mIU/L (n=174) were confirmed to have congenital hypothyroidism at mean (SD) age of 5 (4) days. A good correlation between capillary TSH level and confirmatory venous fT4 level and postnatal age of sampling was obtained (r -0.6, -0.4). The area under the ROC curve (AUC) was 0.81 (95%CI 0.75 to 0.88), indicating referral capillary TSH level of 20 mIU/L to be a good predictor of subsequent high venous TSH level. A cut off of ≥20 mIU/L for capillary TSH screening beyond 24 hours of life is optimal in the Indian setting for deciding further recall and workup, keeping a balance between sensitivity and recall rate.

Background: Physiological changes in maternal thyroid function during pregnancy necessitate the use of pregnancy-specific reference ranges. Dynamic changes in thyrotropin (TSH) within the first trimester of pregnancy have been reported, but more evidence is needed to substantiate the findings. The objective of this study was to estimate pregnancy week-specific reference ranges for maternal TSH and free thyroxine (fT4) in early pregnancy. Methods: The study consecutively recruited serum residues from blood samples collected as part of the prenatal screening in the North Denmark Region, 2011-2015. TSH, fT4, thyroid peroxidase antibodies (TPOAb), and thyroglobulin antibodies (TgAb) were measured using an ADVIA Centaur XPT immunoassay. The reference cohort included 10,337 pregnant women who had no thyroid disease or other autoimmune diseases and were TPOAb- and TgAb negative. The main outcome measures were lower and upper reference limits (2.5th and 97.5th percentiles) for TSH and fT4 stratified by week of pregnancy. Results: Blood samples were drawn in pregnancy weeks 4-20 (median week 10), and 92% of the pregnancies ended with a live birth. TSH varied considerably in the first trimester of pregnancy, and the levels were highest in early pregnancy (weeks 4-6: 0.6-3.7 mIU/L) followed by a gradual decline to lower levels in weeks 9-11 (0.1-2.8 mIU/L) and 12-14 (0.03-2.8 mIU/L). Maternal fT4 showed less variation (weeks 4-6: 12-20 pmol/L; weeks 9-11: 13-21 pmol/L; weeks 12-14: 13-20 pmol/L). Conclusions: The results corroborate dynamic week-specific changes in maternal TSH in early pregnancy. The use of uniform lower and upper reference limits for TSH in early pregnancy may be too simple.

One-hundred four persons aged ≥ 18 years (62 males and 42 females) who were admitted for traumatic brain injury (TBI) underwent brain computed tomography (CT) scan and assay of serum cortisol, insulin-like growth factor 1 (IGF-1), thyrotropin (TSH) and free thyroxine (FT4). The main purpose was to assess any gender difference and the rate of empty sella (ES).Women were more likely to have empty sella (19/42 [45.2%] vs 19/62 [30.6%], P = 0.15, OR = 1.9), which was more frequently total ES or TES (16/19 [84.2%] vs 3/19 [15.8%], P = 0.0025, OR = 11.6). Neuroradiology was normal in the remaining 65 patients. Patients with TES were approximately 20–30 years older than both patients with partial ES (PES) and normal sella, but only the comparison with normal sella was significant (P = 0.001 all patients, P = 0.005 males). Presumed deficiency of IGF-1, cortisol or TSH occurred in 33 persons (31.7%; 20 Males [32.2%], 13 Females [30.9%]), 14 (13.5%; 10 M [16.2%], 4F [9.5%]) or 8 (7.7%; 1 M [1.7%], 7F [16.7%]), with only TSH deficiency having significant intergender difference (P = 0.007). The highest or lowest rates of IGF-1 deficiency occurred in men with PES (41.7%) or men with TES (14.3%), of cortisol deficiency in men with PES (33.3%) or women with PES (zero), and TSH deficiency in women with TES (18.7%) or both men and women with PES (zero) and men with normal sella (zero). Within ES, males with no deficiency were older compared to males with at least one hormone deficiency (75.7 ± 17.4 vs 55.6 ± 18.9, P = 0.022); in turn, the former males were also older compared with normal sella males having no hormone deficiency (54.1 ± 25.2, P = 0.023).In conclusion, ES is detectable in almost 40% of persons who undergo CT within 24 h from TBI. A number of intergender differences concerning ES and the hormones evaluated are apparent. Keywords: Traumatic brain injury, Post-traumatic hypopituitarism, Empty sella, Computed tomography

OBJECTIVE To examine the effect of different limits of acceptability on the Hoffmann method for selecting "healthy" populations from laboratory test data. METHODS Thyroid stimulating hormone (TSH) and free thyroxine (FT4) were measured in Shunyi Maternal and Children's Hospital of Beijing Children's Hospital. The sample size of participants of TSH and FT4 for reference intervals (RIs) establishment was 10,864 and 10,799, respectively. RIs were calculated by Hoffmann method with different acceptable deviations (α value). The validation data was collected prospectively and the out-of-range (OOR) values were calculated to examine the applicability of RIs with different acceptable deviations. The sample size for RIs validation was 880 and 867, respectively. The RIs were considered as valid when OOR was

Nonylphenol (NP) is an endocrine-disrupting chemical (EDC) that can lead to thyroid disruption. We explored NP-induced toxicity in the rat thyroid and evaluated the mitigating effects of mulberry crude extract (MCE) on NP toxicity. First, we aimed to evaluate NP-induced thyroid disruption by dosing Sprague–Dawley (SD) rats with NP (0, 30, 90, or 270 mg/kg body weight) daily for 28 days. Second, we aimed to determine whether MCE had a detoxifying effect on NP-induced thyroid disruption by dosing SD rats with NP (270 mg/kg body weight) or/and MCE (30, 60, or 120 mg/kg body weight) daily for 28 days. We found that NP significantly inhibited free triiodothyronin (FT3) and free thyroxine (FT4) activity in rat serum (P

Previous studies have suggested that even in euthyroid subjects, thyroid function may affect the risk factors of diabetic nephropathy (DN). Thus, we investigated the association between thyroid parameters and DN in euthyroid subjects with type 2 diabetes mellitus (T2DM). This was a cross-sectional study of 1,071 euthyroid subjects with T2DM (mean age of 61.90 ± 12.74 years; 622 men). Clinical factors, including levels of free triiodothyronine (FT3), free thyroxine (FT4), thyroid-stimulating hormone (TSH), thyroid autoantibodies, albumin excretion rate were measured. DN was present in 400 (37.35%) individuals. Patients with DN exhibited higher serum TSH and lower serum FT3 and FT4 levels than those without DN (P

The present study evaluated influence of boiled sausages consumption fortified with β-CD-I2 on the urinary iodine excretion (UIE) level of volunteers. Median urinary UIE level was increased from 58.02 (24.0–175.4) μg/L to 110.6 (20.5–231.6) μg/L during 10 days. Thyroid stimulating hormone (TSH) and free thyroxine (FT4) levels were determined by radio immunoassay analysis. As it was expected, intake of sausages fortified with β-CD-I2 resulted in rise of FT4 level from 1.1 (0.95–1.25) to 1.23 (1.07–1.63) ng/dL, whereas TSH level decreased from 1.53 (0.47–3.37) mIU/L to 1.1 (0.51–3.17) mIU/L. A dynamic gastrointestinal model in vitro was used in order to determine possibility of 3,5-diiodotyrosine (DIT) formation during consumption of the fortified sausages. The DIT concentration was determined by HPLC–MS method and was found to be 0.38 ng/mL in sausage dialyzate. These findings indicate that β-CD-I2 introduction as an iodine carrier in boiled sausages may help to improve iodine status and to control organic iodine species concentration.