Normal Thyroid Hormone Levels Research Articles

Association between eating speed and atherosclerosis in relation to growth differentiation factor-15 levels in older individuals in a cross-sectional study

Although fast eating speed has been associated with cardiovascular risk factors, no studies have reported an association between fast eating speed and atherosclerosis as evaluated by carotid intima–media thickness (CIMT). Rapid glucose ingestion is known to cause glucose spikes, which may accelerate atherogenesis and increase levels of growth differentiation factor 15 (GDF-15). Therefore, GDF-15 levels may influence the association between fast eating speed and atherosclerosis. To evaluate the association between eating speed and atherosclerosis in relation to GDF-15, this cross-sectional study analyzed 742 Japanese aged 60–69 years. They were required to have normal thyroid hormone levels, because both GDF-15 levels and atherosclerosis (CIMT ≥ 1.1 mm) can be influenced by thyroid dysfunction. Participants were stratified by the median GDF-15 level. A significant positive association was observed between fast eating speed and atherosclerosis, but only among participants with a high GDF-15 level: the sex- and age-adjusted odds ratios (95% confidence intervals) were 1.95 (1.09, 3.48) in participants with a high GDF-15 level, and 0.83 (0.37, 1.88) in those with a low GDF-15 level. This association remained even after further adjustment for thyroid function and metabolic factors. Serum concentrations of GDF-15 may mediate the association between fast eating speed and atherosclerosis.

Alterations in Body Weight and Composition in Patients With Graves' Disease Treated with Total Thyroidectomy.

Thyrotoxicosis causes excess energy expenditure, resulting in weight loss, despite increased appetite, and changes in body composition, which are typically reversible with the normalization of thyroid hormone levels. However, patients with hyperthyroidism due to Graves' disease are sometimes hesitant to undergo treatment because of the perceived morbidity associated with weight gain. Therefore, obtaining data to explain the details of such weight gain to these patients is important. This study aimed to investigate changes in body weight and composition in patients with Graves' disease after total thyroidectomy. In total, 21 patients with Graves' disease who underwent total thyroidectomy were enrolled. Among them, nine patients were hyperthyroid (group A) and 12 were euthyroid (group B, control) immediately before surgery. Body weight, height, and body composition using bioelectrical impedance were measured preoperatively and five months postoperatively. In all patients, body weight, body mass index, and skeletal muscle mass, but not fat mass, significantly increased postoperatively. In individual groups, a significant increase in skeletal muscle and fat masses was observed solely in groups A and B, respectively. Furthermore, a significant positive correlation between preoperative thyroid function and differences in skeletal muscle mass preoperatively and postoperatively was found. Our study shows that the normalization of thyroid function using thyroidectomy in patients with Graves' disease is accompanied by weight gain, mainly due to an increase in skeletal muscle mass. These data are clinically significant because they enable physicians to explain to patients that weight gain after surgical treatment for Graves' disease is favorable and reassure them of their concern.

Thyrotoxicosis in Partial Mola Hidatidosa

Thyrotoxicosis is a clinical condition associated with excessive thyroid hormone levels. Symptoms can range from asymptomatic to life-threatening due to thyroid storm. Thyrotoxicosis in hydatidiform moles is a rare condition but has a high mortality rate, so etiological studies are still needed for optimal management. Case Report: Patient Mrs. T, 25 years old Hindu, Balinese, 12 weeks pregnant (Gravida 1 Para 0 abortion 0), came to the obstetrics ER on September 24, 2023 with complaints of discharge from the birth canal since the morning, nausea (+), often shaking, easily tired and often sweaty. physical examination obtained blood pressure 100/60mmHg, pulse 78x/min, respiratory rate 20x/min, axillary temperature 36.80C oxygen saturation 99%. From obstetric examination, fundus uteri height ½ center, vaginal toucher vulva vagina within normal limits, portiono (-) fluxus (+), laboratory examination obtained HCG 387,392.8 mIU/m, FT4 31.05 pmol/L (N: 9-22), TSH <0.01 uIU/mL (N: 0.4-4.2) ultrasound results describe honey comb appearance and histopathology results describe partial mola. Evacuation by curettage was performed, resulting in reduced serum ?-hCG levels and reduced thyroid hormone levels. Discussion: The patient was diagnosed with partial hydatidiform mole and thyrotoxicosis. Hydatidiform moles can cause thyrotoxicosis. This condition is caused by the structure of ?- hCG which resembles TSH so that it can activate TSH receptors. After evacuation of hydatidiform moles, normal TSH and FT4 levels will be obtained. Conclusion: The female patient with thyrotoxicosis due to hydatidiform moles had the moles evacuated, resulting in normal thyroid hormone levels.

Subclinical hypothyroidism in Wales from 2000 to 2021: A descriptive cohort study based on electronic health records.

Subclinical hypothyroidism (SCH) is a biochemical thyroid disorder characterised by elevated levels of Thyroid Stimulating Hormone (TSH) together with normal levels of thyroid hormones. Evidence on the benefits of treatment is limited, resulting in persistent controversies relating to its clinical management. This study describes the demographic and clinical characteristics of patients identified as having subclinical hypothyroidism in Wales between 2000 and 2021, the annual cumulative incidence during this period and the testing and treatment patterns associated with this disorder. We used linked electronic health records from SAIL Databank. Eligible patients were identified using a combination of diagnostic codes and Thyroid Function Test results. Descriptive analyses were then performed. 199,520 individuals (63.8% female) were identified as having SCH, 23.6% (n = 47,104) of whom received levothyroxine for treatment over the study period. The median study follow-up time was 5.75 person-years (IQR 2.65-9.65). Annual cumulative incidence was highest in 2012 at 502 cases per 100,000 people. 92.5% (n = 184,484) of the study population had TSH levels between the upper limit of normal and 10mIU/L on their first test. 61.9% (n = 5,071) of patients identified using Read v2 codes were in the treated group. 41.9% (n = 19,716) of treated patients had a history of a single abnormal test result before their first prescription. In Wales, the number of incident cases of SCH has risen unevenly between 2000 and 2021. Most of the study population had mild SCH on their index test, but more than a third of the identified patients received levothyroxine after a single abnormal test result. Patients with clinically recorded diagnoses were more likely to be treated. Given the expectation of steadily increasing patient numbers, more evidence is required to support the clinical management of subclinical hypothyroidism.

A Case of Peptic Ulcer in Recent Op/C/O Total Thyroidectomy: A Rare Case Report

Gastric acid secretion induces the inner lining of the gastrointestinal tract to rupture, which is the hallmark of peptic ulcer disease. It mainly affects the stomach and proximal duodenum, but it can also affect the lower esophagus, distal duodenum, or jejunum. The two main factors interfering with the mucosal resistance to damage are H. pylori and NSAIDs. Goitre is a disorder characterized by an enlarged thyroid gland that may or may not be linked to hyper or hypothyroidism. It can be manifested with normal thyroid hormone levels (euthyroid). Both the entities are different. Here, we describe a case of peptic ulcer discovered in a patient who had undergone a total thyroidectomy recently for a massive diffuse nodular goitre.

Clinical features of neonatal hyperthyroidism: a retrospective analysis in southwestern China.

This study aimed to explore the clinical characteristics and evaluate the different types of thyroid dysfunction in babies with neonatal hyperthyroidism. The clinical data of 19 neonates with hyperthyroidism admitted to the Children's Hospital of Chongqing Medical University between January 2012 and April 2021 were retrospectively analyzed. Fifteen (78.9%) infants were born to mothers with Graves' disease. Eleven (57.9%) infants were premature; two babies were born at small for gestational age. The age at diagnosis ranged from 3 to 34 days, with a mean of 18.53 ± 6.85 days. The majority of the babies presented with goiter (84.2%) and tachycardia (94.7%) after birth. Nine (47.4%) of them presented with abnormal weight gain, seven (36.8%) presented with stare or ocular protrusion, six (31.6%) presented with hyperexcitability, four (21.1%) presented with jaundice and liver dysfunction, two (10.5%) presented with sweating, one (5.3%) presented with fever, and one case presented without any symptoms. Transient hyperthyroidism was the main thyroid dysfunction in our study. Overt hyperthyroidism was diagnosed in 13 (68.4%) neonates. Another three babies (15.8%) presented with hyperthyroidism with slightly elevated free triiodothyronine levels, normal thyroxine (T4) levels, and low thyroid-stimulating hormone (TSH) levels. Normal thyroid hormone levels with low TSH levels were observed in three (15.8%) neonates. Ten children were treated with antithyroid drugs. Eighteen children recovered normal thyroid function at 1-3 months of age; one baby in the study group required further levothyroxine supplementation due to primary hypothyroidism (HT). One child was found to have developmental delay at 2 years of age during follow-up. Our study highlights the need for prolonged monitoring of thyroid function in suspected patients. A single normal screening for hyperthyroidism or the absence of a maternal history of hyperthyroidism cannot exclude this disease.

Associations between cardiovascular health and low thyroid function among US adults: a population-based study.

Higher thyroid-stimulating hormone (TSH) amidst normal thyroid hormone (TH) levels may contribute to a negative impact on cardiovascular health (CVH). We sought to probe the associations between Life's Essential 8 (LE8), a newly revised CVH evaluation, and low thyroid function among US adults. The datasets from the 2007-2012 National Health and Nutrition Examination Survey (NHANES) were applied to the study. Low-normal thyroid function and subclinical hypothyroidism (SCH) were both regarded to be low thyroid function. Multivariable logistic regressions were utilized to inquire about the relationship between LE8 and low thyroid function. Among the 6,315 participants (age ≥20 years), 1,375 (21.77%) were ascertained to be low thyroid function. After adjusting possible confounders, a higher LE8 score was linked to a lower probability of experiencing low thyroid function (Odds ratio [OR] for each 10-point increase: 0.923 [95% CI, 0.884-0.964]). A similar correlation was found between the health factors score and low thyroid function (OR for each 10-point increase: 0.905 [95% CI, 0.876-0.935]). Also, scoring better on physical activity (PA), body mass index (BMI), blood lipid, blood glucose (BG), and blood pressure (BP) may be conducive to reducing the rates of low thyroid function. Furthermore, subgroup and sensitivity analyses indicated that the negative correlations were generally robust. The LE8 score and health factors score were nonlinearly and negatively related to the prevalence concerning low thyroid function. Promoting the regulation of optimum CVH levels could work on mitigating the load of low thyroid function and cardiovascular diseases (CVDs).

A Review on Hashimoto’s Thyroiditis

Hashimoto's thyroiditis (HT) is an autoimmune thyroid disorder first described by Japanese physician Haraku Hashimoto in 1912 characterized by lymphocytic infiltration of the thyroid parenchyma and is influenced by immune system instability. The onset of autoimmunity may be influenced by innate and acquired immune responses. Thyroid autoantibodies (TAbs) are the primary biochemical feature. Epidemiological studies show AITD (autoimmune thyroid disease) risk is higher in women and is age-related. Risk factors include high iodine consumption, selenium insufficiency, infectious disorders, and specific medications. Genetic predisposition and environmental factors also contribute to HT. Pregnancy and sex steroids play a role in the development of autoimmune thyroiditis, with older women being more susceptible. The immune system is modified during pregnancy, with progesterone playing a significant role. About 20% of postpartum thyroiditis patients eventually develop HT. The symptoms include dysphonia, dyspnea, and dysphagia, with primary hypothyroidism causing greater systemic symptoms. Diagnosis involves circulating thyroid-specific antibodies, ultrasound examination, increased thyroid stimulating hormone, and normal serum thyroid hormone levels. Ultrasonography is crucial for diagnosing Hashimoto's thyroiditis, distinguishing it from other thyroid disorders like Graves' disease (GD). The treatment comprises levothyroxine, which effectively lowers thyroid volume, as well as vitamin D deficiency and replacement. Autoimmune thyroiditis (AIT) surgery has traditionally been reserved for people who have discomfort or compressive symptoms from goitre or co-existing malignant thyroid nodules. Thyroidectomy has lately been advocated as a treatment option for decreasing TPOAbs, as the presence of such antibodies is linked to a worse quality of life even in euthyroid patients.
 Keywords: Hashimoto’s thyroiditis (HT), Autoimmune thyroid disease (AITD), Autoimmune thyroiditis (AIT) Vitamin D , Levothyroxine

A Clinical Audit of Thyroid Hormonal Replacement After Total Thyroidectomy.

Background Thyroid hormone replacement (THR) in athyreotic patients post-thyroidectomy due to thyroid cancer might seem like a straightforward clinical issue to address. To investigate the impact of THR on enhancing thyroid-stimulating hormone (TSH) levels, we conducted a clinical audit, tailoring the dosage based on patient weight and aligning with the standards outlined by the National Institute for Health and Care Excellence and the American Thyroid Association guidelines. Methodology This retrospective and prospective audit analyzed outpatient clinic records for hormone replacement therapy (HRT) post-total thyroidectomy. Retrospective data from March to May 2022 were collected, followed by prospective data after interventions adjusting HRT based on patient weight to digitize clinic notes. The second phase involved changes for 20 scheduled thyroidectomy patients among the total 37 included in the study. Results The thyroid profiles of both groups in the initial and subsequent cycles, treated with adjusted doses of THR, exhibited normal levels of thyroid hormones and calcium. No substantial differences were observed between the groups. On multivariate logistic regression analysis, we found that older age, male sex, body mass index, and preoperative TSH level were the only significant predictors of the need for hormonal therapy. Conclusions Optimal dose of THR after total thyroidectomy had a positive effect on TSH levels in hypothyroidism patients. Hence, THR should be prescribed according to patient weight based on standards and guidelines.

Advancing Preoperative Strategies for Thyroidectomy in Graves' Disease: A Narrative Review.

Graves' disease is an autoimmune disorder characterized by thyroid-stimulating antibodies that can potentially lead to thyrotoxicosis, goiter, skin disease, and eye disease. Available treatment options for Graves' disease include management with antithyroid drugs (ATDs), thyroid ablation with radioactive iodine (RAI), and surgical thyroid gland removal. For individuals unable to reach a normal thyroid hormone level, promptly considering a thyroidectomy is essential. Preoperative strategies to achieve a euthyroid state prevent thyroid storms and minimize postoperative complications and are therefore crucial. While variations in professional guidance exist, this review focuses on standard medical interventions as well as compares respective guidelines set forth by the American Thyroid Association, the European Thyroid Association, the American Association of Clinical Endocrinology, and the American Association of Endocrine Surgeons. There is consensus among these organizations underscoring the importance of rendering patients euthyroid prior to surgery and the use of ATDs. Most guidelines recommend screening for vitamin D deficiency as well as endorse thyroidectomy as the preferred treatment option for hyperthyroidism with skilled surgeons. Nevertheless, discrepancies do become apparent in aspects such as potassium iodide (SSKI) course duration and preoperative dexamethasone administration. By understanding these differing approaches, healthcare professionals can more effectively manage Graves' disease prior to surgery, resulting in improved patient outcomes and enhanced surgical success.

The dangerous trend of levothyroxine medicalization

Thyroid hormone replacement is paramount in overt hypothyroidism; recently, however, thyroid hormone substitution is increasingly prescribed to patients with normal thyroid hormone levels. This forum article discusses the complex causes and the possible negative effects of overusing thyroid hormone replacement drugs.

The conundrum of acute onset midline neck swellings: a unique case report of a thyroid abscess

The conditions of the thyroid gland are the most common causes for midline neck swellings and present with a spectrum of clinical features and differential diagnosis, some more fatal than the others. One such rare yet worrisome condition is suppurative thyroiditis progressing to an abscess. A 17 year old male presented with an acute neck swelling with fever, pain, and hoarseness of voice. Investigations revealed leucocytosis with normal thyroid hormone levels. Contrast enhanced CT scan of the neck showed presence of an abscess of the thyroid gland with left sided tracheal shift. Incision and drainage with antibiotic support was done leading to an uneventful recovery. The thyroid gland by virtue of its capsule, rich blood supply, and high iodine content is resistant to infection. Thyroid abscess is a rare condition with high morbidity and mortality. This condition should be a differential diagnosis in cases of acute onset midline swellings. Immediate surgical drainage of the collection with antibiotic support is the gold standard treatment of this condition.

Changes in brain structure in subjects with resistance to thyroid hormone due to THRB mutations

BackgroundBeing critical for brain development and neurocognitive function thyroid hormones may have an effect on behaviour and brain structure. Our exploratory study aimed to delineate the influence of mutations in the thyroid hormone receptor (TR) ß gene on brain structure.MethodsHigh-resolution 3D T1-weighted images were acquired in 21 patients with a resistance to thyroid hormone ß (RTHß) in comparison to 21 healthy matched-controls. Changes in grey and white matter, as well as cortical thickness were evaluated using voxel-based morphometry (VBM) and diffusion tensor imaging (DTI).ResultsRTHß patients showed elevated circulating fT4 & fT3 with normal TSH concentrations, whereas controls showed normal thyroid hormone levels. RTHß patients revealed significantly higher scores in a self-rating questionnaire for attention deficit hyperactivity disorder (ADHD). Imaging revealed alterations of the corticospinal tract, increased cortical thickness in bilateral superior parietal cortex and decreased grey matter volume in bilateral inferior temporal cortex and thalamus.ConclusionRTHb patients exhibited structural changes in multiple brain areas. Whether these structural changes are causally linked to the abnormal behavioral profile of RTHß which is similar to ADHD, remains to be determined.

Lower free triiodothyronine levels are associated with higher all-cause and cardiovascular mortality in people with diabetes-NHANES 2007–2012

ObjectiveThyroid hormone plays a key role in maintaining cardiovascular system homeostasis. However, there is limited evidence regarding the correlation between normal range thyroid hormone levels and all-cause mortality or cardiovascular mortality among individuals with diabetes. MethodThis retrospective study analyzed data from 1,208 individuals with diabetes who participated in the National Health and Nutrition Survey (NHANES) conducted in the United States between 2007 and 2012. Weighted Kaplan-Meier (KM) analysis and Cox proportional hazards models were used to explore the association between thyroid hormone indices and mortality. ResultsThe Weighted Kaplan-Meier (KM) analysis revealed statistically significant differences in survival probabilities across free triiodothyronine (FT3), free thyroxine (FT4), FT3/FT4 ratio and thyroid-stimulating hormone (TSH) groups (p < 0.05 or < 0.001). In the multivariate adjusted Cox proportional hazards models, higher levels of FT3 were founded to be associated with decreased all-cause mortality (HR (95% CI), 0.715 (0.567, 0.900)), cardio-cerebrovascular mortality (0.576 (0.408, 0.814)) and cardiovascular mortality (0.629 (0.438, 0.904)). Notably, this correlation was more significant among individuals over the age of 60, as indicated by the results of the nonlinear regression analysis. ConclusionFT3 is an independent predictor of all-cause death, cardio-cerebrovascular and cardiovascular death in euthyroid subjects with diabetes.

Alterations of Thyroid Hormone Levels and the Risks of Diabetic Retinopathy in T2DM

Background: Diabetes mellitus and thyroid disease are linked endocrinopathies. The association between diabetes mellitus complications and thyroid function is characterized by a complicated interdependent interplay that is difficult to understand. Objective: We conducted this study to determine the association between diabetic retina disease (DRD) incidence and normal thyroid hormone levels in T2DM. Methods: Recruit patients in the study, 134 patients with type 2 diabetes and 36 healthy ones with no DM, were screened in the present case-control study. Diabetic retinopathy was tested for all patients, and anthropometric and thyroid functions were assessed. Regression analyses were employed to evaluate the relationship between thyroid hormones and the risk of developing DR. Results: There were significant differences in triiodothyronine (T3) and thyroxine (T4) serum levels among the DR groups and the healthy control. The levels in each TSH and T4 are positively significant between groups of PDR and NDR, while T3 was negatively associated with NPDR. A significant association was found between increasing levels of T3 and the development of severe DR; thus, PDR was less likely to occur in individuals with high T3 levels‎ [OR 0.014(95% CI, 0.001-0.34) P value is 0.009 after adjustment. The risk of PDR had an increased likelihood of developing PDR at the highest levels of serum TSH and T4 [OR 41.07(1.60-1053.1) P= 0.025, OR 65.91(2.10-2067) P= 0.017, respectively). Conclusion: Diabetes retinopathy in euthyroid Iraqi people may be associated with levels of T3 and T4 in the blood. Patients with higher TSH and T4 concentrations had a greater risk of developing sight-threatening PDR in type 2 diabetics.

MODERN ASPECTS OF THE TREATMENT OF PATIENTS WITH AUTOIMMUNE THYROIDITIS

The relevance of the problem is due to the continuous increase in morbidity and the lack of effectiveness of existing treatment methods. The aim of the study is to improve the treatment results of patients with autoimmune thyroiditis by introducing modern laser technology. The study was conducted retrospectively from 2008 to 2021 and is based on data from the examination and treatment of 481 patients with autoimmune thyroiditis. The patients were divided into groups according to the applied treatment methods: the first group - 129 (29,19%) patients, the second group - 106 (23,98%) patients, and the third group - 207 (46,83%) patients. The concentrations of thyroid hormones, pituitary gland and antibodies to thyroid tissues in the blood serum of patients before and after treatment were studied and compared. Long-term treatment results were studied in 340 (70,7%) patients (t=8,8, p≤0,001). Photodynamic therapy, in combination with sessions of intravenous laser blood irradiation with lowintensity laser radiation, contributed to the normalization of thyroid hormone levels (TSH, FT4 and FT3) of the thyroid gland on the 15th day of treatment. Combining conservative treatment of patients with autoimmune thyroiditis with photodynamic therapy allows to obtain good and satisfactory results in 77,5% of cases, which gives reason to recommend photodynamic therapy in combination with sessions of intravenous laser blood irradiation with low-intensity laser radiation as an effective way to complement traditional conservative treatment

Association Between Sensitivity to Thyroid Hormone Indices and Diabetic Retinopathy in Euthyroid Patients with Type 2 Diabetes Mellitus.

Normal thyroid hormone (TH) levels and their relation to microvascular complications in patients with type 2 diabetes mellitus (T2DM) have been studied. However, the relationship between TH sensitivity and diabetic retinopathy (DR) remains unclear. Thus, this study aimed to investigate the relationship between TH sensitivity and the risk of DR in euthyroid T2DM patients. This retrospective study analyzed 422 T2DM patients and calculated their sensitivity to TH indices. Multivariable logistic regression, generalized additive model, and subgroup analysis were performed to examine the association between sensitivity to TH indices and DR risk. After adjusting for covariates, the binary logistic regression model showed no statistically significant association between the sensitivity of TH indices and the risk of DR in euthyroid T2DM patients. However, a non-linear relationship was found between sensitivity to TH indices (thyroid-stimulating hormone index, thyroid feedback quantile index [TFQI]) and the risk of DR in the crude model; TFQI and DR in the adjusted model. The inflection point of the TFQI was 0.23. The effect size (odds ratio) on the left and right of the inflection point were 3.19 (95% confidence interval [CI]: 1.24 to 8.17 p=0.02) and 0.11 (95% CI: 0.01, 0.93 p=0.04), respectively. Moreover, this relationship was maintained by men stratified by sex. In euthyroid patients with T2DM, an approximate inverted U-shaped relationship and a threshold effect were demonstrated between TH index sensitivity and DR risk with sex differences. This study provided an in-depth understanding of the relationship between thyroid function and DR, which has important clinical implications for risk stratification and individual prediction.

Evaluation of an Association of Thyroid Disorder and Dyslipidemia in Patients with Cardiovascular Disease: A Cross-sectional Study

Background: Subclinical Hypothyroidism (SCH) is defined as normal serum free thyroid hormone levels coexisting with elevated serum Thyroid-Stimulating Hormone (TSH) levels. SCH is a common condition observed in clinical practice with several unique features. The present study was conducted to find prevalence of subclinical hypothyroidism in patients with myocardial infarction and demographic differences between patients with and without SCH. Materials and Methods: A total of 100 patients with Myocardial Infarction of Adult (age &gt; 18 years) males and females were selected from the patients attending Medicine OPD, IPD or Intensive Care Unit (ICU) in GMC, Azamgarh. Clinical examination, laboratory investigations for myocardial infarction, thyroid status and lipid profile was done in all patients in our study. All Patients with TSH values &gt; 10mU/L or &lt; 0.04mU/L or Known cases of Thyroid abnormalities were excluded from the study. Statistical analysis was done using excel and SPSS software. Results: Out of 100 patients 44 patients of MI had subclinical hypothyroid were as rest 56 patients were euthyroid. In both the groups no statistical difference was seen in the type of Myocardial infarction. There was significant difference in lipid profile (p&lt;0.05) in SCH group as compared to euthyroid group. Conclusion: Patients with Subclinical hypothyroid and MI had more lipid abnormalities as compared to Euthyroid group although the type of myocardial infarction was similar in both the groups. Males had more myocardial infarction as compared to females in both the subclinical hypothyroid and euthyroid groups.

Challenges in Thyroid Function Testing: Interferences and Clinical Implications

In recent decades, significant advancements have been made in the methodologies used for evaluating thyroid dysfunctions. These advancements include the development of radioimmunoassays, immunometric assays, and liquid chromatography coupled with mass spectrometry. The main thyroid function tests include thyroid-stimulating hormone (TSH) and the measurement of triiodothyronine (T3) and thyroxine (T4), including their total and free fractions. Over time, different generations of TSH tests have been developed, starting from radioimmunoassays to immunometric assays, and more recently, tests utilizing fluorophores and chemiluminescent molecules. The third-generation tests are currently the most widely used due to their high sensitivity and specificity. Thyroid-stimulating hormone is preferred as the initial test for evaluating thyroid function since it has a log-linear relationship with free T4 levels, enabling the identification of subclinical hypothyroidism and subclinical hyperthyroidism. The reference range for normal TSH levels is typically between 0.45 and 4.5 mIU/L. However, there can be variations in TSH levels based on factors such as sex, age, and ethnicity. Specific reference values may be required for certain populations, such as the elderly, pregnancy, and neonates. In the elderly, an increase in TSH levels is expected. In the neonatal period, TSH levels are high after birth and take a few weeks to normalize. During pregnancy, various physiological changes occur, leading to alterations in thyroid hormones to meet fetal demands. Laboratory interferences in thyroid hormone assays must be considered to ensure accurate results. Biotin interference can lead to falsely low TSH and falsely high free T3 and T4 levels. Macro-thyrotropin can cause elevated TSH levels with normal thyroid hormone levels. Heterophilic antibodies can also cause false results. Additionally, the evaluation of autoantibodies and markers used in thyroid cancer follow-up needs special attention. Patients experiencing conditions like trauma, particularly in severe cases, may undergo changes in thyroid hormone levels, even without having a specific thyroid disease, which is called low triiodothyronine syndrome. In conclusion, it is essential to be aware of potential laboratory interferences and consider individual variations to ensure accurate interpretation and appropriate management of patients.

Study of thyroid function among COVID-19-affected and non-affected people during pre and post-vaccination.

The novel coronavirus COVID-19 has caused a global pandemic with many long-ranging effects on the physiological balance of the human body. The impact of COVID-19 on the thyroid axis remains uncertain. Our aim was to assess the long-term consequences of COVID-19 infection and its vaccination with thyroid hormones. Thirty laboratory-confirmed COVID-19-positive patients with no vaccination record, thirty COVID-19-negative patients with vaccination records, and ten healthy subjects were retrospectively, and cross-sectionally enrolled in this study. An ELISA assay was performed to evaluate thyroid function tests, including the total triiodothyronine (TT3), total thyroxine (TT4), and thyroid stimulating hormone (TSH). We found decreased levels of TT3, average or low plasma T4 levels, and standard or slightly decreased TSH levels in unvaccinated COVID-19-positive patients than in the healthy group, while the vaccinated COVID-19-negative group had normal thyroid hormone levels compared to controls. The correlation between TT3 and TSH levels gradually shifted from no association to a negative pattern in the unvaccinated COVID-19-positive group. Again, a highly significant negative correlation between TSH and TT3 was observed on days above 150, although a slight fluctuation was noted on day 90. This pilot study from Bangladesh shows that abnormalities in thyroid function can be observed during COVID-19 infection and after vaccination, which gradually recovers over time.