Subclinical hypothyroidism

2011 ◽  
pp. 543-547
Author(s):  
Jayne A. Franklyn
Keyword(s):  
Thyroid Function ◽  
Subclinical Hypothyroidism ◽  
Expert Panel ◽  
Elevated Serum ◽  
Thyroid Stimulating Hormone ◽  
Free Thyroxine ◽  
Thyroid Function Tests ◽  
Free Triiodothyronine ◽  
Function Tests ◽  
Serum Tsh

Subclinical hypothyroidism is defined biochemically as the association of a raised serum thyroid-stimulating hormone (TSH) concentration with normal circulating concentrations of free thyroxine (T4) and free triiodothyronine (T3). The term subclinical hypothyroidism implies that patients should be asymptomatic, although symptoms are difficult to assess, especially in patients in whom thyroid function tests have been checked because of nonspecific complaints such as tiredness. An expert panel has recently classified individuals with subclinical hypothyroidism into two groups (1): (1) those with mildly elevated serum TSH (typically TSH in the range 4.5–10.0 mU/l) and (2) those with more marked TSH elevation (serum TSH >10.0 mU/l).

scholarly journals Report of the IFCC Working Group for Standardization of Thyroid Function Tests; Part 2: Free Thyroxine and Free Triiodothyronine

2010 ◽  
Vol 56 (6) ◽  
pp. 912-920 ◽  
Author(s):  
L. M. Thienpont ◽  
K. Van Uytfanghe ◽  
G. Beastall ◽  
J. D. Faix ◽  
T. Ieiri ◽  
...  
Keyword(s):  
Thyroid Function ◽  
Working Group ◽  
Free Thyroxine ◽  
Thyroid Function Tests ◽  
Free Triiodothyronine ◽  
Function Tests

scholarly journals Routine free thyroxine reference intervals are suboptimal for monitoring children on thyroxine replacement therapy and target intervals need to be assay-specific

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Elizabeth Wheeler ◽  
Kay Weng Choy ◽  
Lit Kim Chin ◽  
Nilika Wijeratne ◽  
Alan McNeil ◽  
...  
Keyword(s):  
Thyroid Function ◽  
Reference Intervals ◽  
Clinical Diagnostics ◽  
Free Thyroxine ◽  
Thyroid Function Tests ◽  
Free Triiodothyronine ◽  
Central Hypothyroidism ◽  
Thyroxine Replacement ◽  
Ortho Clinical Diagnostics ◽  
Serum Tsh

AbstractCentral hypothyroidism is a condition where there is (qualitatively or quantitatively) TSH deficiency, leading to reduced thyroid hormone production. In such patients, serum TSH does not accurately reflect the adequacy of thyroxine replacement, as the log-linear relationship between thyrotropin (TSH) and free thyroxine (FT4) is lost. We aimed to prospectively determine the optimal physiological FT4 treatment range for children treated for primary hypothyroidism, based on their serum TSH concentrations. This information could be used to guide optimal therapy for all children on thyroxine replacement, including those with central hypothyroidism. In total, sixty children (median age: 11 years, range: 11 months to 18 years) were recruited over 21 months. They were prescribed a stable dose of thyroxine for at least 6–8 weeks prior to a thyroid function test that consisted of serum TSH, FT4 and free triiodothyronine (FT3) measurements. The serum sample for the thyroid function tests was collected before ingestion of the daily dose, i.e. the trough concentration, and measured using Beckman Coulter UniCel DxI 800 instrument, Siemens Advia Centaur, Roche Cobas, Abbott Architect, Ortho Clinical Diagnostics Vitros 5600 (Ortho-Clinical Diagnostics, Raritan, NJ) platforms. The FT4 and FT3 reference intervals showed significant inter-method difference. The lower limit of the FT4 reference intervals were generally shifted mildly higher when the TSH concentration of the children were restricted from 0.5–5.0 mIU/L to 0.5–2.5 mIU/L. By contrast, the upper limit of the FT3 and FT4 reference intervals were relatively stable for the different TSH concentrations. Assay-specific target ranges for optimal thyroxine therapy are required until FT4 assay standardisation is realised.

scholarly journals Euthyroid Sick Syndrome in Pulmonary Tuberculosis before and after Treatment

1995 ◽  
Vol 32 (4) ◽  
pp. 385-391 ◽  
Author(s):  
C C Chow ◽  
T W L Mak ◽  
C H S Chan ◽  
C S Cockram
Keyword(s):  
Pulmonary Tuberculosis ◽  
Thyroid Hormones ◽  
Thyroid Function ◽  
Thyroid Stimulating Hormone ◽  
Significant Rise ◽  
Chinese Patients ◽  
Thyroid Function Tests ◽  
Free Triiodothyronine ◽  
Euthyroid Sick Syndrome ◽  
Function Tests

Alterations of circulating thyroid hormones are frequently present in chronic nonthyroidal illnesses and may predict prognosis. Pulmonary tuberculosis, a common treatable debilitating disease, may provide a useful model for detailed evaluation of changes of thyroid hormones in relation to subsequent recovery or mortality. Over a period of 12 months, we performed a prospective study of 40 consecutive Chinese patients aged over 50 years and admitted with newly diagnosed pulmonary tuberculosis. Blood samples were drawn for serial thyroid function tests [free thyroxine (T4), free triiodothyronine (T3) and thyroid-stimulating hormone] before treatment and at 1, 2 and 4 months afterwards. Mortality was determined up to 12 months of follow-up. The euthyroid sick syndrome occurred in 63% of patients at presentation. Twelve of 25 euthyroid sick patients died as compared to one of 15 patients with normal baseline thyroid function tests ( P < 0·02). Among euthyroid sick patients, those who died had significantly lower free T3 concentration at presentation than those who survived ( P < 0·05). An undetectable free T3 concentration at presentation was associated with a subsequent mortality of 75% (9 of 12). Of the survivors, all patients demonstrated a significant rise in serum free T4 concentrations following treatment, which was apparent by 1 month. These data suggest that an undetectable free T3 concentration at presentation reflects severity of illness and predicts a subsequent high mortality.

scholarly journals Altered Thyroid Function Tests Observed in Hypophosphatasia Patients Treated with Asfotase Alfa

2021 ◽  
Vol 2021 ◽  
pp. 1-5
Author(s):  
Hajime Kato ◽  
Naoko Hidaka ◽  
Minae Koga ◽  
Yuka Kinoshita ◽  
Masaomi Nangaku ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Function ◽  
Magnetic Beads ◽  
Underlying Mechanism ◽  
Thyroid Stimulating Hormone ◽  
Thyroid Function Tests ◽  
Free Triiodothyronine ◽  
Asfotase Alfa ◽  
Function Tests ◽  
One Step

Background. Asfotase alfa is the only approved treatment that can normalize mineralization in patients with hypophosphatasia (HPP). Its interference in alkaline phosphatase (ALP) dependent immunoassays has been reported. Objective. To describe thyroid function tests interfered with by asfotase alfa and elucidate the underlying mechanism. Patients and Methods. Three patients with HPP treated with asfotase alfa were included. Thyroid hormone levels measured using five different immunoassays with or without ALP as a labeling enzyme during asfotase alfa treatment were evaluated. Results. After the initiation of asfotase alfa, three HPP patients showed low free triiodothyronine (FT3) and free thyroxine (FT4) measured with AIA-2000 (Tosoh, Tokyo, Japan), an enzyme immunoassay system that uses ALP as a labeling enzyme, but their thyroid-stimulating hormone (TSH) levels were within the normal range. The other CLEIA system using ALP as a label, AIA-CL2400 (Tosoh, Tokyo, Japan), and ALP-independent immunoassay systems demonstrated normal FT3 and FT4 levels. These data suggested that although the thyroid function of these three patients was normal, asfotase alfa interfered with the thyroid hormone measurements made with AIA-2000. AIA-2000 and AIA-CL2400 adopted one-step and delayed one-step measurements, respectively, and the same antibody was used for both immunoassays. However, asfotase alfa may be absorbed on the magnetic beads used in the AIA reagent with the AIA-2000 system but not absorbed on the microparticles used in AIA-CL2400. Conclusion. Clinicians should be aware of the possible interference in thyroid function measurements by adopting specific types of immunoassays in asfotase alfa-treated HPP patients.

THYROID FUNCTION TESTS: A REVIEW

2021 ◽  
pp. 73-76
Author(s):  
Vasudev Sankhla ◽  
Aman Deep
Keyword(s):  
Thyroid Function ◽  
Thyroid Dysfunction ◽  
Radioactive Iodine ◽  
Thyroid Stimulating Hormone ◽  
Thyroid Function Tests ◽  
Function Tests ◽  
Tsh Secretion ◽  
Line Test ◽  
Radioactive Iodine Uptake

Thyroid function tests are one of the most common endocrine panels in general practice because a good understanding of when to order them, indications for treatment are important for the optimal treatment of thyroid dysfunction. Thyroid-stimulating hormone (TSH) should be the rst test to be performed on any patient with suspected thyroid dysfunction and in follow-up of individuals on treatment. It is useful as a rst-line test because even small changes in thyroid function are sufcient to cause a signicant increase in TSH secretion. Thyroxine levels may be assessed in a patient with hyperthyroidism, to determine the severity of hyperthyroxinemia. Antithyroid peroxidase measurements should be considered while evaluating patients with subclinical hypothyroidism and can facilitate the identication of autoimmune thyroiditis during the evaluation of nodular thyroid disease. The measurement of TSH receptor antibody must be considered when conrmation of Graves’ disease is needed and radioactive iodine uptake cannot be done.

scholarly journals The Characteristics of Children with Abnormalities Detected in Thyroid Function Tests, and Distribution of Diagnoses

2020 ◽  
Author(s):  
Elif Çelik ◽  
Ayşe Anık
Keyword(s):  
Thyroid Function ◽  
Thyroid Disease ◽  
Correct Diagnosis ◽  
Thyroid Function Test ◽  
Hashimoto Thyroiditis ◽  
Thyroid Stimulating Hormone ◽  
Thyroid Function Tests ◽  
Test Results ◽  
Function Tests ◽  
Function Test

INTRODUCTION: Thyroid function tests are among the most frequently implemented laboratory tests in primary, and secondary healthcare institutions. The aim of the present study was to investigate the demographic and clinical characteristics and final diagnosis of children referred by primary and secondary healthcare institutions with the suspicion of an abnormality in thyroid function test and/or with the initial diagnosis of specific thyroid disease. METHODS: A total of two hundred eighty-nine pediatric patients, aged between 4 and 18 years admitted to the outpatient clinics of Behçet Uz Children’s Health and Diseases Hospital between January 2018 and January 2020, were included in the study. The patient data were obtained retrospectively from the hospital records. RESULTS: A total of 66% of the patients who were included in the study were female with a median age of 12 years (8.7-14.4), while 64% of them were pubertal; and 78% of the cases were referred by secondary healthcare institutions. The most common reason for referral was isolated elevation of thyroid stimulating hormone (TSH). A total of 56% of the patients were asymptomatic at the time of admission, and thyroid function test results of 75% of them were within normal limits. When evaluated according to their final diagnoses, the children were normal/healthy (64%), diagnosed with Hashimoto thyroiditis (30%), nodular thyroid disease (3%), Graves disease (2%) and isolated increase of TSH was related to obesity in 5 patients (1%). DISCUSSION AND CONCLUSION: It is essential to evaluate children with abnormal thyroid function test results with detailed history and physical examination. Besides, the thyroid function tests should be performed with reliable and sensitive methods in standardized laboratories to reach the correct diagnosis in these children.

scholarly journals Thyroid Function Changes and Pubertal Progress in Females: A Longitudinal Study in Iodine-Sufficient Areas of East China

2021 ◽  
Vol 12 ◽  
Author(s):  
Yingying Wang ◽  
Dandan He ◽  
Chaowei Fu ◽  
Xiaolian Dong ◽  
Feng Jiang ◽  
...  
Keyword(s):  
Linear Regression ◽  
Multiple Linear Regression ◽  
Thyroid Function ◽  
Pubertal Development ◽  
Thyroid Stimulating Hormone ◽  
East China ◽  
Regression Analyses ◽  
Free Triiodothyronine ◽  
Serum Tsh

BackgroundThe onset of puberty is influenced by thyroid function, and thyroid hormones (THs) fluctuate substantially during the period of pubertal development. However, it needs to be further clarified how THs change at specific puberty stages and how it influences pubertal development in girls. So far, longitudinal data from China are scarce.MethodsA cohort study was conducted among girls during puberty in iodine-sufficient regions of East China between 2017 to 2019. Serum thyroid stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxine (FT4) were determined for each participant. Thyroid homeostasis structure parameters (THSPs), including the ratio of FT4 to FT3 (FT4/FT3), Jostel’s TSH index (TSHI), and thyroid feedback quantile-based index (TFQI), were calculated. Puberty category scores (PCS), calculated based on the Puberty Development Scale (PDS), was used to assess the stage of puberty. Girls were grouped into three categories according to PCS changes (△PCS) and six categories according puberty stage (BPFP: pre-pubertal at both baseline and follow-up; BPFL: pre-pubertal at baseline and late-pubertal at follow-up, respectively; BPFT: pre-pubertal at baseline and post-pubertal at follow-up, respectively; BLFL: late-pubertal at both baseline and follow-up; BLFT: late-pubertal at baseline and post-pubertal at follow-up, respectively; BTFT: post-pubertal at both baseline and follow-up). Multiple linear regression analyses were used to evaluate the associations of THs changes with pubertal progress.ResultsThe levels of serum TSH and FT3 decreased while serum FT4 increased during the study period (P&lt;0.001). In multiple linear regression analyses, after adjustment for covariables, FT3 decreased by an additional 0.24 pmol/L (95% CI: -0.47 to -0.01) in the higher △PCS group than the lower △PCS group. Compared with the BLFL group, the BPFT group showed an additional decline in FT3 (β= -0.39 pmol/L, 95%CI: -0.73 to -0.04), the BTFT group showed a lower decline in TSH (β=0.50 mU/L, 95% CI: 0.21 to 0.80) and a lower decline in TSHI (β=0.24, 95%CI: 0.06 to 0.41), respectively. There was no association of △FT4 or △TFQI with △PCS or the puberty pattern.ConclusionsSerum TSH and FT3 decreased while serum FT4 increased among girls during puberty. Both the initial stage and the velocity of pubertal development were related to thyroid hormone fluctuations.

scholarly journals A comparative study on outcomes of preprandial versus postprandial thyroid function test

2019 ◽  
Vol 5 (6) ◽  
pp. 1662
Author(s):  
Vasim Ismail Patel ◽  
Akshay B. K.
Keyword(s):  
Thyroid Function ◽  
Subclinical Hypothyroidism ◽  
Clinical Symptoms ◽  
Thyroid Function Test ◽  
Thyroid Stimulating Hormone ◽  
Endocrine Gland ◽  
Thyroid Function Tests ◽  
Sample Collection ◽  
Free T4 ◽  
Group 2

<p class="abstract"><strong>Background:</strong> The thyroid is an<strong> </strong>endocrine gland. It secretes two hormones thyroxine (T<sub>4</sub>), triiodothyronine (T<sub>3</sub>). Hypothyroidism is a common condition encountered by a clinician. Subclinical hypothyroidism (SCH) defined as normal free thyroxine (T4) and elevated thyroid stimulating hormone (TSH), is primarily a biochemical diagnosis with or without clinical symptoms. Studies have observed that TSH levels vary at different times in a day. In practice not much importance is given to the timing of the sample collection (pre-prandial or post-prandial sate). SCH is diagnosed depending on TSH value. So the condition may be under or over diagnosed based on a single value. So we conducted this study to determine whether timing of sample collection had any significant relationship in the determination of levels of thyroid hormones.</p><p class="abstract"><strong>Methods:</strong> The study was carried on 114 patients who visited ENT department, NMCH between July 2018 and June 2019. Group-1 consisted of 38 normal patients. Group-2 consisted of 36 hypothyroidism patients GROUP-3 consisted of 40 subclinical hypothyroidism patients. Thyroid function tests (TSH and free T4) were done in fasting state and 2 hours postprandially.  </p><p class="abstract"><strong>Results:</strong> TSH values were found to be significantly lowered after food in all the three groups. Free T4 values did not show any statistically significant alteration after food.</p><p class="abstract"><strong>Conclusions:</strong> There was a significant decline in TSH values postprandially. This might lead to inappropriate diagnosis and management of patients as cases of hypothyroidism, especially in cases of sub clinical hypothyroidism.</p>

Subclinical hyperthyroidism

2011 ◽  
pp. 461-465
Author(s):  
Jayne A. Franklyn
Keyword(s):  
Expert Panel ◽  
Normal Values ◽  
Thyroid Stimulating Hormone ◽  
Subclinical Hyperthyroidism ◽  
Free Triiodothyronine ◽  
Biochemical Diagnosis ◽  
Undetectable Serum ◽  
Detectable Serum ◽  
Serum Tsh ◽  
Low Serum

Subclinical hyperthyroidism is defined biochemically as the association of a low serum thyroid-stimulating hormone (TSH) value with normal circulating concentrations of free thyroxine (T4) and free triiodothyronine (T3). The biochemical diagnosis of subclinical hyperthyroidism is dependent upon the use of sensitive assays for TSH able to distinguish normal values found in euthyroid people from reduced values, so our understanding of this topic has accumulated in recent years since such assays became widely available. An expert panel has recently classified patients with subclinical hyperthyroidism into two groups (1): (1) those with low but detectable serum TSH (0.1–0.4 mU/l) and (2) those with undetectable serum TSH (<0.1 mU/l) reflecting the fact that studies of this condition largely divide people into these categories and that the likely consequences reflect the biochemical severity of the condition.

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