Thyroid-stimulating Hormone Assay Research Articles

Incidence and risk factors associated with the development of hypothyroidism after postoperative chemoradiotherapy for head and neck cancer patients with high-risk features: Supplementary analysis of JCOG1008

Background and purposeHypothyroidism is a recognized late adverse event following radiotherapy for head and neck cancer (HNC). In the JCOG1008 trial, we treated patients with high-risk HNC with postoperative chemoradiotherapy. We aimed to elucidate factors associated with hypothyroidism by analyzing the JCOG1008 data. Materials and methodsIn 2012–2018, 261 patients from 28 institutions were enrolled in JCOG1008. Thyroid function tests were conducted to assess hypothyroidism, including free thyroxine (FT4) and thyroid-stimulating hormone assays. Hypothyroidism was defined as Grade 2 or higher in CTCAE v4.0. Various clinical and dosimetric parameters were analyzed. In radiotherapy, there were no dose constraints for the thyroid. Multivariable analysis was conducted on these variables to identify predictive factors for hypothyroidism. ResultsThe analysis included 162 patients (57 with 3D-CRT and 105 with IMRT), with a median follow-up of 4.7 years (0.3–9.3 years). Among these, 27 (16.7 %) developed hypothyroidism within 2 years after radiotherapy. In a multivariable analysis, the weekly cisplatin [OR=7.700 (CI: 1.632–36.343, p = 0.010)] and baseline FT4 [OR=0.009 (CI: <0.001–0.313, p = 0.010)] were significantly associated with hypothyroidism in the IMRT group. Regarding dosimetric characteristics, V60Gy [OR=1.069 (CI: 0.999–1.143, p = 0.054)] was potentially associated with the development of hypothyroidism. ConclusionThe study revealed that the incidence of hypothyroidism within 2 years after postoperative chemoradiotherapy for high-risk HNC was 16.7 % based on analytical results from prospective clinical trials.

Verification of the analytical performance of the thyroid stimulating hormone assay on Alinity I ® experience from the biochemistry laboratory of Mohammed VI university hospital in Oujda

Verification of the analytical performance of the thyroid stimulating hormone assay on Alinity I ® experience from the biochemistry laboratory of Mohammed VI university hospital in Oujda

Evaluation of a novel, sensitive thyroid-stimulating hormone assay as a diagnostic test for thyroid disease in cats.

Clinicians commonly use thyroid-stimulating hormone (TSH) concentrations to diagnose thyroid disorders in humans and dogs. In cats, canine TSH chemiluminescent immunoassays (CLIA) assays are commonly used to measure TSH, but these TSH-CLIAs cannot measure low TSH concentrations (< 0.03 ng/mL) and therefore cannot distinguish between low-normal concentrations and truly low TSH concentrations (characteristic of hyperthyroidism). Our aim was to evaluate a novel TSH assay based on bulk acoustic wave (BAW) technology that has lower functional sensitivity (0.008 ng/mL) than TSH-CLIAs. 169 untreated hyperthyroid cats, 53 cats treated with radioiodine (131I), 12 cats with chronic kidney disease (CKD), and 78 clinically healthy cats. Serum concentrations of T4, TSH-CLIA, and TSH-BAW were measured in all cats. Untreated hyperthyroid cats were divided into 4 severity groups (subclinical, mild, moderate, and severe), whereas 131I-treated cats were divided into euthyroid and hypothyroid groups. Test sensitivity, specificity, and positive predictive value for identifying hyperthyroidism were higher for TSH-BAW (90.5%, 98.9%, and 86.9%) than TSH-CLIA (79.9%, 76.7%, and 21.7%; P < .001). Test sensitivity for identifying 131I-induced hypothyroidism was only 45.5% for T4 versus 100.0% for both TSH-CLIA and TSH-BAW (P = .03), whereas TSH-BAW had a higher positive predictive value (100%) than did either TSH-CLIA (81.2%) or T4 (71.9%). Serum TSH-BAW alone or together with T4 is a highly sensitive and specific diagnostic test for evaluating feline hyperthyroidism and iatrogenic hypothyroidism. Finding low serum TSH-BAW concentrations is most useful for diagnosing subclinical and mild hyperthyroidism, in which serum T4 remains within or only slightly above the reference interval.

The negative impact of levothyroxine treatment on urinary luteinizing hormone measurements in pediatric patients with thyroid disease.

Previous studies suggest urinary luteinizing hormone (LH) and follicle-stimulating hormone (FSH) measurements by immunofluorometric assays (IFMA) as noninvasive alternatives to serum assays for puberty assessment. However, these studies excluded patients with other endocrine disorders and those taking medications. Besides, the recent discontinuation of IFMA manufacturing is a concern. We explored the utility of luminometric assays (LIA) for urinary gonadotropins and thyroid-stimulating hormone (TSH) determinations in euthyroid patients with thyroid pathologies. We used LIA and IFMA assays to measure serum and first-morning-voided (FMV) urine LH, FSH, and TSH concentrations in euthyroid patients with various thyroid disorders. Of the 47 euthyroid patients with normal serum TSH (S-TSH) levels, 14 were receiving levothyroxine therapy. FMV total urinary LH (U-LH) concentrations correlated significantly with those measured in serum using either LIA (r=0.67, P<.001) or IFMA (r=0.83, P=.003) in patients not receiving levothyroxine treatment; however, no significant correlation could be detected in patients receiving levothyroxine regardless of the assay method (for LIA: r=0.50, P=.08 and IFMA r=0.44, P=.15). Urinary TSH (U-TSH) concentrations correlated poorly with those in serum in both the untreated and the treated groups (r=-0.13, P=.49, and r=-0.45, P=.11, respectively). FMV total U-LH determinations by LIA can be used to assess pubertal development in patients with thyroid pathology, provided the euthyroid patient is not on levothyroxine treatment. U-TSH measurements by LIA cannot replace invasive S-TSH measurements at least in patients with normal S-TSH levels. Further research may reveal the utility of U-TSH determinations in patients with elevated S-TSH levels.

Interference of heterophilic antibodies with thyroid stimulating hormone (TSH) assay leading to inappropriate treatment

Interference of heterophilic antibodies with thyroid stimulating hormone (TSH) assay leading to inappropriate treatment

A-024 Evaluation of the Analytical Performance of Thyroid-stimulating Hormone, Free Triiodothyronine, and Free Thyroxine Assays on the Atellica CI 1900 Analyzer

Abstract Background The Atellica® CI 1900 Analyzer is an automated, mid-throughput integrated chemistry and immunoassay analyzer utilizing both Atellica CH and Atellica IM assays. This study evaluated the analytical performance of the Atellica IM Thyroid Stimulating Hormone 3 Ultra™ (TSH3-UL), Free Triiodothyronine (FT3), and Free Thyroxine (FT4) assays* on the Atellica CI 1900 Analyzer. Methods The Atellica CI 1900 TSH3-UL, FT3, and FT4 assays use the same reagents and calibrators as the Atellica IM assays. Precision and method comparison studies were performed according to CLSI EP05-A3 and CLSI EP09-A3 using native and contrived human serum (TSH3-UL, FT3, and FT4) and plasma (TSH3-UL) samples. One aliquot of each sample pool was tested in duplicate in two runs per day &amp;gt;2 h apart on each analyzer for ≥20 days. FT3 and FT4 were evaluated with one reagent lot on two systems. TSH3-UL was evaluated with two reagent lots on two systems. For the method comparison, individual native human serum samples were analyzed using the Atellica IM TSH3-UL, FT3, and FT4 assays on both the Atellica IM and Atellica CI 1900 Analyzers. Results Representative precision and MC results are listed for each assay in the table. Slopes determined by the Deming linear regression model were approximately equal to 1. Conclusion Evaluation of the Atellica IM TSH3-UL, FT3, and FT4 assays using the Atellica CI 1900 Analyzer demonstrated good precision and equivalent performance compared to the same assays on the Atellica IM Analyzer. *The products/features mentioned herein are not commercially available in all countries. Their future availability cannot be guaranteed.

A-050 Understanding the Complex Relationship Between TSH and Free Thyroxine

Abstract Background Guidelines suggest screening for thyroid disease using thyroid stimulating hormone (TSH) first before free thyroxine (fT4) since there is an inverse log-linear relationship between them; the signal favors TSH over fT4 in a ratio of &amp;gt;100:2. We reassessed this fT4 to TSH relationship following the improved 3rd generation TSH assay from Roche (since 09/2019). Methods Consecutive paired TSH/fT4 (n = 7484) from distinct ambulatory non-hospitalized subjects that were assayed on cobas e801 were retrieved from our laboratory information system and combined with similar data from Kuala Lumpur Hospital (n = 11 369) that were assayed on cobas e601. Reference intervals and measuring limits for the Roche assays were 0.4–4.0 μIU/L and 0.005–100 μIU/L for TSH, and fT4 10–20 pmol/L and 0.3–100 pmol/L for fT4, respectively. Values outside the reportable limits (n = 618) were excluded. Descriptive statistics, linear and nonparametric (kernel) regression were performed using the statistical software packages in R 4.2.0. Results Linear regression of logTSH against fT4 (n = 18 235) gave an r = −0.35. Nonparametric regression revealed two negative sigmoid curves merging into the euthyroxinemic region (see Graph). Three different segments can be discerned; hypothyroxinemic (fT4 &amp;lt; 10): logTSH = 1.91–0.136fT4 (n = 422; r = −0.39, P &amp;lt; 0.001), euthyroxinemic (fT4 10–20): logTSH = 0.672–0.028fT4 (n = 15 754, r = −0.13, P &amp;lt; 0.001), and hyperthyroxinemic (fT4&amp;gt;20): logTSH = 1.106–0.055fT4 (n = 2059, r = −0.33, P &amp;lt; 0.001). Conclusion The relationship between fT4 and TSH is complex. The widely accepted view of a constant gradient of logTSH against fT4 over the whole range of thyroid test values is inaccurate. Three distinct relationships correspond to each biochemical thyroid status. In the hypothyroxinemic and hyperthyroxinemic range, TSH increases almost 5-fold and 13-fold with a doubling of fT4, respectively. In the euthyroxinemic range, there is no relationship between logTSH and fT4. While a TSH first strategy is applicable in hypo/hyperthyroxinemia, both TSH/fT4 are still required to confirm diagnoses and for baseline assessment prior to commencing therapy.

Development of a quantitative thyroid-stimulating hormone assay system for a benchtop digital ELISA desktop analyzer.

Regular checkups for thyroid-stimulating hormone (TSH) levels are essential for the diagnosis of thyroid disease. The enzyme-linked immunosorbent assay (ELISA) technique is a standard method for detecting TSH in the serum or plasma of hospitalized patients. A recently developed next-generation ELISA, the digital immunoassay (d-IA), has facilitated detection of molecules with ultra-high-sensitivity. In this study, we developed a TSH assay system using the d-IA platform. By utilizing the ultrasensitivity of d-IA, we were able to use a sample volume of as little as 5µL for each assay (the dead volume was 5µL). The limits of blank, detection, and quantification (i.e., functional sensitivity), were 0.000346, 0.001953, and 0.002280μIU/mL, respectively, and the precision of the total coefficient of variation did not exceed 10%. The correlation between serum and plasma levels indicated good agreement. Thus, our system successfully measured TSH using d-IA with a small sample volume and equal functional sensitivity to the current third generation like ARCHITECT TSH assay, which has a functional sensitivity of 0.0038μIU/mL.

Association of Thyroid Function With Lipid Profile in Patients With Metabolic Syndrome: A Prospective Cross-Sectional Study in the Indian Population.

Introduction Metabolic syndrome is a group of aberrant metabolic indicators including hypertension, dyslipidemia, impaired fasting blood glucose, and obesity. It has been reported that thyroid hormones have a strong influence on the cardiovascular system, and hypothyroidism has been linked to metabolic syndrome components. The objective of the study was to find out the association of thyroid function with lipid profile in patients with metabolic syndrome. Methods A prospective cross-sectional study was conducted in an apparently healthy adult population visiting the outpatient Department of Indira Gandhi Institute of Medical Sciences (IGIMS), Patna, Bihar, India. Metabolic syndrome was diagnosed according to the International Diabetes Federation (IDF) criteria. Fasting blood glucose, triglyceride, and HDL levels were tested using the enzymatic photometric method. Thyroid-stimulating hormone (TSH), free T4, free T3, and insulin assays were performed using chemiluminescence immunoassay (CLIA). Results Out of 197 subjects recruited, 86 (51 males and 35 females) were diagnosed with metabolic syndrome according to the IDF criteria, and the rest 111 without metabolic syndrome were considered to be the controls. The mean age of subjects with and without metabolic syndrome was 45.8±8.5 and 46.4±9.6 years, respectively. The prevalence of thyroid dysfunction in the present study was 22%. In subjects with metabolic syndrome, most of the clinical and hormonal parameters (waist circumference, waist-height ratio, fasting blood sugar, fasting insulin, triglycerides, T3, and TSH) were significantly higher (p<0.001) as compared to those without metabolic syndrome. In case of lipid profile, the triglycerides in those with metabolic syndrome (262.8±112.3 mg/dL) were significantly higher (p<0.001) than those without metabolic syndrome (137.9±19.01 mg/dL), while the serum levels of HDL were significantly higher (p<0.001) in group without metabolic syndrome (50.5±3.9 mg/dL) as compared to those with metabolic syndrome (43.4±5.2 mg/dL). Also, the TSH levels were significantly higher (p<0.001) in subjects with metabolic syndrome (5.3±3.4 μl/mL) as compared to those without metabolic syndrome (2.6±1.4 μl/mL). Among all the components of metabolic syndrome, waist circumference and HDL showed a significant strong positive correlation (r=0.51) with TSH, and systolic blood pressure (r=0.39), diastolic blood pressure (r=0.39), and fasting blood sugar levels (r=0.44) showed significantly moderate positive correlation with TSH levels. T4 (OR=8.82; 95% CI: 1.56-49.8) and TSH (OR=1.61; 95% CI: 1.19-2.18) levels were observed to have significantly higher odds as risk factors for metabolic syndrome. Conclusion There is a significant association of thyroid function with lipid profile in metabolic syndrome. It was observed that along with metabolic alterations, cardiovascular symptoms of hypothyroidism and subclinical hypothyroidism are possible. Therefore, while evaluating people with metabolic syndrome, it may be appropriate to look into how well their thyroid glands are functioning.

How low can we (reliably) go? A method comparison of thyroid-stimulating hormone assays with a focus on low concentrations.

International guidelines concerning subclinical hyperthyroidism and thyroid cancer advice absolute cut-off values for aiding clinical decisions in the low range of thyroid-stimulating hormone (TSH) concentrations. As TSH assays are known to be poorly standardized in the normal to high range, we performed a TSH assay method comparison focusing on the low range. Sixty samples, selected to cover a wide range of TSH concentrations (<0.01 to 120 mIU/L) with oversampling in the lower range (<0.4 mIU/L), were used for the method comparison between three TSH immunoassays (Cobas, Alinity and Atellica). In addition, 20 samples were used to assess the coefficient of variation from duplicate measurements in these three methods. The TSH immunoassays showed standardization differences with a bias of 7-16% for the total range and 1-14% for the low range. This could lead to a different classification of 1.5% of all measured TSH concentrations <0.40 mIU/L measured in our laboratory over the last 6 months, regarding the clinically important cut-off value of TSH = 0.1 mIU/L. As the imprecision of the immunoassays varied from 1.6-5.5%, this could lead to a similar reclassification as the bias between immunoassays. We established the standardization differences of frequently used TSH assays for the total and low concentration ranges. Based on the proportional bias and the imprecision, this effect seems to have limited clinical consequences for the low TSH concentration range. Nevertheless, as guidelines mention absolute TSH values to guide clinical decision-making, caution must be applied when interpreting values close to these cut-offs.

Human T-cell leukemia virus type 1 is associated with dysthyroidism in the French Amazon.

Human T-cell leukemia virus type 1 (HTLV-1) is a retrovirus known to cause two major diseases: adult T-cell leukemia/lymphoma and a progressive neuromyelopathy-tropical spastic paraparesis. Many viruses may be involved in the pathogenesis of thyroiditis; however, few studies have focused on the role of HTLV-1. We aimed to investigate the association between HTLV-1 and biological thyroid dysfunction. We included 357 patients with a positive HTLV-1 serology and thyroid-stimulating hormone assay data between 2012 and 2021 in a hospital in French Guiana; we compared the prevalence of hypothyroidism and hyperthyroidism in this group with that in an HTLV-1-negative control group (722 persons) matched for sex and age. The prevalence of hypothyroidism and hyperthyroidism in patients with HTLV-1 infection was significantly higher than that in the control group (11% versus 3.2% and 11.3% versus 2.3%, respectively; p < 0.001). Our study shows, for the first time, the association between HTLV-1 and dysthyroidism in a large sample, suggesting that thyroid function exploration should be systematically implemented in this population as this may have an impact on therapeutic management.

Frequency of Hyperthyroidism in patients of Atrial Fibrillation

Aim: To find the frequency of hyperthyroidism in patients of atrial fibrillation admitted in Mayo hospital Lahore. Study setting: The study was conducted at Emergency Department, Cardiology Department and Department of Internal Medicine in Mayo Hospital Lahore\ Duration of study: It was from May 20, 2019 to November 20, 2019. Study design: It was Cross-Sectional study\ Methods: patients suffering with atrial fibrillation fulfilling the operational definition and inclusion criteria were enrolled. After aseptic measures, blood sample of 5 ml was drawn from left cubital vein with low sucking pressure. Sample was deposited to Center for Nuclear Medicine (CENUM) Laboratory at Mayo Hospital Lahore for thyroid function tests. Serum Thyroid Stimulating Hormone, Thyroxine and Triiodothyronine levels were noted and hyperthyroidism labeled as per the operational definition. Data was collected by the researcher himself noted on a specially designed proforma and presented in the form of tables and diagrams. Results: The mean value of age in our study was 55.13±14.01 year. In our study 40(42.6%) patients had hyperthyroidism. Conclusion: High frequency of hyperthyroidism in our study, suggests that routine thyroid function tests using sensitive thyroid-stimulating hormone assay with free T4 &amp; free T3 levels is required in all those with acute atrial fibrillation. Keywords: Hyperthyroidism, Atrial Fibrillation.

Stability of Thyroid Function Test Analytes Whose Serum Levels Are Determined by Immunoassay

We have performed stability studies on thyroid function tests, i.e., T4, T3, free T4, free T3 and thyroid stimulating hormone (TSH), over a five-day period on the sera of ten patients. We find that the levels for each analyte were stable; the mean coefficients of variation (CV) ranged from 3.2 % for TSH to 8.7% for T4. ANOVA statistical analysis of group means for each analyte over the five-day period indicated that there was no statistically significant difference in these means, confirming the reproducibility of values. On the other hand, the CVs are significantly larger than those found in our prior stability studies for other critical analytes such as electrolytes (sodium, potassium, chloride, calcium). In addition, significant variations in values over the five-day period occurred for T4 which showed the largest variations in values of the five analytes studied. In one patient, the values ranged from a low of &lt;10 ug/dL to over 14 ug/dL over the five-day period. A two-tailed t test comparing the mean CV for TSH with the mean CVs of the other four analytes showed that the mean CV for TSH was statistically significantly lower than that for the other four analytes indicating that the assay for TSH yield the most precise results. These results parallel those obtained in our prior electrolyte study that showed very low CVs for sodium, potassium and chloride and a significantly higher CV for calcium. Since approximately half of total serum calcium is bound to albumin and since very high percentages of T4 and T3 (≥99%) are bound to thyroid binding globulin and albumin, protein binding of these analytes may introduce a possible source of assay imprecision.

LEVELS OF SERUM TSH AND ITS IMPLICATIONS IN DEVELOPMENT OF METABOLIC SYNDROME – TIP OF THE ICEBERG: IN YOUNG ADULTS OF GUWAHATI CITY.

Thyroid Stimulating Hormone (TSH) is a hormone secreted by the anterior pituitary that plays an important role in regulating the function of the thyroid gland. Levels of TSH in the blood - is a reliable index of the functional status of the thyroid gland. At present, TSH levels in serum are estimated by microparticle enzyme immuno assays (MEIA), which are very sensitive. In the current study, serum TSH levels were measured in 100 clinically euthyroid subjects, consisting of 50 males and 50 females. The study found that 12% of the subjects (5 males and 7 females) had TSH values above the normal, the normal range of the TSH assay being 0.35-4.50 m IU/ml. This nding is signicant in light of the recent focus on subclinical hypothyroidism being in limelight, particularly the risk of development of overt thyroid dysfunction in persons with high normal values of serum TSH. Furthermore, such kind of studies in general population among young population was done rarely previously, as a reection of their serum TSH levels in this part of the India who are considered euthyroid till the time they were tested. Moreover, detection of subclinical or overt hypothyroid state helps in the preventive aspects as well as to nd out other parameters of metabolic syndrome- which is considered now as just the tip of the iceberg. In the study, serum TSH levels were measured in 100 eut Materials and methods: hyroid subjects (50 males and 50 females) by microparticle enzyme immune assay. After analyzing the values of TSH i Results: t was detected that 12% of the subjects (5 males and 7 females) had TSH levels &gt;4.50 m IU/ml (Upper limit of the normal range). This nding is Conclusion: signicant in light of the recent focus on subclinical hypothyroidism being particularly at the risk of development of overt thyroid dysfunction in young age leading to a gamut of metabolic disorders and mortality &amp; morbidity occuring among such populace at a young age Further, it is of importance that such type of lifestyle modiable disorders can be prevented or reverted to normal if detected early.

2021 Asia-Pacific Graves' Disease Consortium Survey of Clinical Practice Patterns in the Management of Graves' Disease.

Although Graves' disease (GD) is common in endocrine practices worldwide, global differences in diagnosis and management remain. We sought to assess the current practices for GD in countries across Asia and the Pacific (APAC), and to compare these with previously published surveys from North America and Europe. A web-based survey on GD management was conducted on practicing clinicians. Responses from 542 clinicians were received and subsequently analysed and compared to outcomes from similar surveys from other regions. A total of 542 respondents participated in the survey, 515 (95%) of whom completed all sections. Of these, 86% were medical specialists, 11% surgeons, and 3% nuclear medicine physicians. In addition to serum thyroid-stimulating hormone (TSH) and free thyroxine assays, most respondents would request TSH-receptor autoantibody (TRAb) measurement (68%) during initial work-up. Thyroid ultrasound is requested by about half of respondents (53%), while the use of nuclear medicine scans is limited. The preferred first-line treatment is anti-thyroid drug (ATD) therapy (79%) with methimazole (MMI) or carbimazole (CBZ), followed by radioiodine (RAI; 19%) and surgery (2%). In case of surgery, one-third of respondents would opt for a subtotal rather than a total thyroidectomy. In case of mild Graves orbitopathy (GO), ATDs (67%) remains the preferred treatment, but a larger proportion of clinicians prefer surgery (20%). For a patient with intention to conceive, the preferred treatment pattern remained unchanged, although propylthiouracil (PTU) became the preferred ATD-agent during the first trimester. In comparison to European and American practices, marked differences were noted in the relatively infrequent usage of nuclear medicine scans and the overall higher use of a ATDs and β-blockers and adjunctive ATD-treatment during RAI in the APAC-group. Although regional differences regarding the diagnosis and management of GD are apparent in this first pan-Asia-Pacific survey, this study reveals the overall approach to the management of this disease in Asia-Pacific generally tends to fall between the trends appreciated in the American and European cohorts.

Thyroid Dysfunction among Hypertensive Pregnant Women in Warri, Delta State, Nigeria.

The hypertensive pregnant woman is at a higher risk of complications either before, during or after birth and the baby can be adversely affected leading to preterm birth, low birth weight, placental separation (abruption) and other complications. The aim of the study was to evaluate thyroid dysfunction among pregnant women with hypertension. The study participants were 150 hypertensive pregnant women, 25 non-hypertensive pregnant women and 25 non-hypertensive non-pregnant women. Exactly 5mL of blood was collected and used for the assay of triiodothyronine (T3), thyroxine (T4) and thyroid-stimulating hormone (TSH) using the enzyme-linked immunosorbent assay technique. Data were analyzed using appropriate statistical tools. The results showed a significantly higher (p < 0.05) age among hypertensive pregnant women when compared with non-hypertensive pregnant women and non-hypertensive non-pregnant women. The serum TSH was significantly higher (p < 0.035) among hypertensive pregnant women when compared with non-hypertensive pregnant women. The triiodothyronine (T3) of hypertensive pregnant women was observed to be significantly higher (p < 0.05) when compared with both non-hypertensive pregnant women and non-hypertensive non-pregnant women. Some 15/150 (10%) of hypertensive pregnant women had subclinical hypothyroidism, 13/150 (8.7%) had overt hypothyroidism, while 122/150 (81.3%) were euthyroid. Among those with thyroid dysfunction, five and four of the subjects had subclinical hypothyroidism and overt hypothyroidism during the second trimester, while ten and nine had subclinical hypothyroidism and overt hypothyroidism during the third trimester, respectively. Evaluation of hypertensive pregnant women for thyroid function may be routinely performed to enable early diagnosis and treatment.

Untreated thyroid autoantibody-negative SCH increases the risk of spontaneous abortions

BackgroundNumerous studies have found that subclinical hypothyroidism (SCH) may increase adverse pregnancy outcomes; however, the benefit of levothyroxine (LT4) treatment remains controversial. The 2017 guidelines of the American Thyroid Association weakly recommended LT4 therapy for serum antithyroid peroxidase antibody (TPOAb)-negative women with thyroid-stimulating hormone (TSH) concentrations greater than the pregnancy-specific reference range and below 10.0 mU/L. Therefore, the primary goal of this study was to investigate the correlation between thyroid autoantibody-negative SCH with or without LT4 treatment and adverse pregnancy outcomes.MethodsWe prospectively enrolled 1868 consecutive pregnant women. Finally, 1344 women were involved in the study according to the inclusion and exclusion criteria. Assays for TSH, free thyroxine (FT4), TPOAb, anti-thyroglobulin antibody, and laboratory indicators were performed. The participants were divided into the euthyroid (ET) group (n = 1250) and the SCH group(n = 94). The SCH group was further divided into LT4 group (n = 40) and non-LT4 group(n = 54). The laboratory indicators and pregnancy outcomes were evaluated during follow-ups.ResultsMaternal age, BMI, parity, and the history of spontaneous abortion did not differ significantly between the ET group and the different SCH groups. There were no significant differences in lipid profile and homocysteine levels between ET and SCH group in the first and third trimester of pregnancy. After adjusting the confounding factors, the non-LT4 group was a risk factor for spontaneous abortion (odds ratio: 3.141, 95% CI: 1.060–9.302). Survival analysis showed that the time of abortion was different between the ET group and SCH group (log-rank P= 0.042). The spontaneous abortion in SCH, especially in non-LT4, group mainly occurred in the first trimester of pregnancy.ConclusionsThyroid autoantibody negative-SCH seems to be associated with increased risk of spontaneous abortions during the first trimester of pregnancy. LT4 therapy in this patient population might be beneficial to reduce adverse pregnancy outcomes.

Cross-sectional prospective feasibility study of newborn screening for sickle cell anaemia and congenital hypothyroidism in Guyana

IntroductionNewborn screening (NBS) is a test done shortly after birth to detect conditions that cause severe health problems if not treated early. An estimated 71% of babies worldwide are born...

Immunoassay design and biotin interference.

Biotin (vitamin B7 or vitamin H), a member of vitamin B complex, acts as a cofactor for five biotin-dependent carboxylases, thus playing critical roles in gluconeogenesis, fatty acid synthesis and amino acid catabolism. Although rare inborn errors of metabolism may cause biotin deficiency, these can be successfully treated with biotin supplementation. In general, normal individuals do not get any benefit from taking biotin supplement. Nevertheless, biotin use remains widespread for growing healthy hair and nail. Unfortunately, the use/overuse of supplemental biotin may interfere with immunoassays that incorporate biotinylated antibody in assay design. Biotin if present in elevated concentration in serum or plasma, may falsely increase analyte concentration using competitive immunoassay (positive interference). In contrast, biotin shows negative interference if sandwich immunoassay format is used. Such interferences may cause diagnostic error, most commonly in cases of hyperthyroidism due to (1) positive interference of biotin in free triiodothyronine (FT3) and free thyroxine (FT4) assays (competitive format) and (2) negative interference in thyroid stimulating hormone (TSH) assay (sandwich format). In this review, I explore the biochemistry of biotin and discuss its role as a potential interferent in immunoassay formats that are biotin based.

Analytical validation of the LiCA® high-sensitivity human thyroid stimulating hormone assay

BackgroundWe aimed to assess the analytical characteristics of a new high-sensitivity human thyroid stimulating hormone (hTSH) assay on a light-initiated chemiluminescent immunoassay system (LiCA Smart) and examine the utility of this assay in the context of profoundly low TSH levels (<0.01 mIU/L). MethodsAnalytical validations included precision, linearity, reportable range, analytical sensitivity, interference, reagent lot-to-lot and between-instrument variability, and method comparisons. Additionally, a cross-sectional study was performed to evaluate the assay for the detection of profoundly low TSH levels in comparison to those of two other ultrasensitive hTSH assays. ResultsWithin-run and within-lab imprecisions (%CV) were < 5% at all concentrations studied. A satisfactory linearity (R = 0.998, change in recovery < 5%) was verified over the entire measuring range. Method comparisons demonstrated a reasonable agreement (R > 0.99, median bias < 5%) between LiCA and Cobas, ADVIA, UniCel or Architect. The limit of quantitation was 0.0019 mIU/L. Comparative measurements of 236 patient samples with profoundly low TSH levels (<0.01 mIU/L) by LiCA, Cobas, and Architect revealed that the detection rate observed with LiCA (67.8%) was significantly higher than that with Cobas (28.0%) or Architect (21.7%). In a further comparative follow-up of patients with overt hyperthyroidism who were receiving treatment, an earlier recovery response of TSH was observed in LiCA. ConclusionsThe LiCA Smart hTSH is a precise and highly sensitive fourth-generation assay. The assay demonstrated superior detection sensitivity for profoundly low TSH levels and was acceptable for clinical use.