Trends in thyroid function following radiofrequency ablation of benign, nonfunctioning thyroid nodules: A single institution review.

BACKGROUND: Radiofrequency ablation (RFA) effectively reduces volume and improves symptoms of benign, non-functioning thyroid nodules (NFTNs). Given RFA's unclear impact on thyroid function, we examined post-RFA trends in thyroid hormones and antibodies. METHODS: A retrospective cross-sectional analysis was conducted of patients treated at Columbia University with RFA for benign NFTNs between August 2019 and July 2023. Thyroid function tests were recorded pre-RFA and repeated 3, 6, and 12 months post-RFA. RESULTS: We analyzed 185 patients with 243 benign NFTNs who underwent RFA. Volume reduction ratio increased post-RFA. Mean TSH increased to 2.4 mlU/L (p â€‹= â€‹0.005) at 3 months post-RFA and decreased to 1.8 mlU/L (p â€‹= â€‹0.551) by 12 months post-RFA. Tg and TPO antibody levels peaked at 6 months post-RFA (103.1 IU/mL, p â€‹= â€‹0.868 and 66.6 IU/mL, p â€‹= â€‹0.523, respectively). CONCLUSIONS: With expected volume reduction post-RFA, we observed transient relative hypothyroidism as well as transient increases in thyroid antibodies, with normalization of these changes within 12 months.

Misleading thyroid function tests in congenital dysfibrinogenemia.

The presence of latent fibrin clots is a recognised pre-analytical factor that causes inaccurate immunoassay results. This report details a case of a patient with Graves' disease and congenital dysfibrinogenemia (CD) that had serum thyroid function test results (TFTs) that were not in keeping with clinical signs or symptoms. Analysis of plasma samples taken from the patient was shown to provide more accurate results than those obtained using serum samples. Further cases of patients with CD, all sharing the same genetic mutation of fibrinogen, and discordant TFTs are described, where TFTs measurement in serum samples proved to be unreliable. Despite evidence of fibrin effecting immunoassays, this is the first report of its kind linking CD to erroneous immunoassay results. The mechanism is postulated to be related to atypical forms of fibrinogen resulting in latent fibrin in serum samples blocking the antigen binding site and leading to incorrect results. Congenital dysfibrinogenemia is asymptomatic in most patients and therefore abnormal, albeit inaccurate, TFTs may be the first finding. Recognition of CD as a cause of discordant results is important when interpreting TFTs to avoid unnecessary investigations and inappropriate clinical interventions to those with the disorder and potentially identify undiagnosed cases.

The Effect of Apalutamide on Thyroid Function in Prostate Cancer Patients.

Context: Apalutamide (APT) is a nonsteroidal antiandrogen medication used to treat metastatic castrate-sensitive and nonmetastatic castrate-resistant prostate cancer. Early clinical trials of APT identified thyroid dysfunction as a common adverse effect of therapy, but the clinical presentation and management of APT-induced hypothyroidism has not been studied. Objective: The objective of our study is to elucidate the clinical presentation and treatment approach of APT-associated thyroid dysfunction in prostate cancer patients. Methods: We report a case series of 16 patients with APT-associated thyroid dysfunction during prostate cancer treatment at 2 academic medical centers. Patient clinical parameters, thyroid function laboratory data, and thyroid hormone requirements over the course of APT treatment were analyzed. Results: Among the 16 patients in our case series with APT-associated hypothyroidism, 3 had no prior thyroid disease and 13 had preexisting hypothyroidism. The patterns of thyroid dysfunction included overt and subclinical hypothyroidism. The median time from APT initiation to thyroid function test abnormality was 19 weeks, but occurred in some cases as early as 2 to 4 weeks. Hypothyroidism was effectively managed with thyroid hormone replacement using levothyroxine (LT4), though some patients with preexisting hypothyroidism required a 2- to 3-fold dose increase while on APT to achieve a euthyroid state. In the subset of patients who completed or stopped APT therapy, thyrotropin levels fell at a median of 11 weeks post APT therapy and thyroid hormone requirements decreased to near pre-APT levels. Conclusion: APT-associated thyroid dysfunction presents as new or worsening hypothyroidism and should prompt initiation or increase in thyroid hormone replacement. Monitoring of thyroid function tests is recommended every 1 to 2 months for all patients on APT and 2 to 3 months after completion of APT.

Gastric bypass surgery in morbid obesity: Influence on thyroid function tests and insulin resistance status.

Background: There are inconsistent results about the effect of gastric bypass surgery on thyroid function tests in morbidly obese subjects. The aim of this study was to investigate the changes in thyroid function tests and insulin resistance status in euthyroid morbidly obese subjects before and three months after gastric bypass surgery (GBS). Methods: Twenty-nine subjects with morbid obesity (BMI≥40) were enrolled in this before-after study. Patients with known thyroid disorders or a history of thyroid ablative therapy, users of drugs that affect thyroid function, or fasting blood sugar and insulin were excluded. TSH, Free T4, total T3, fasting blood sugar and insulin level, and BMI were measured before and 3 months after GBS. Statistical analysis was performed with appropriate tests and p<0.05 was considered significant. Results: Body mass index (BMI), insulin sensitivity index (HOMA-IR), and total T3 significantly decreased after bypass surgery (all with p<0.001) but no significant changes were seen in TSH (P=0.203) and FreeT4 (P=0.33). There was a significant negative correlation between changes in HOMA-IR and changes in FreeT4 (P=0.038, r= -0.38). There was no statistically significant correlation between the percentage of excess BMI loss (%EBMIL) and changes in T3 (P=0.66), Free T4 (P=0.92), TSH (P= 0.27), and HOMA-IR (P=0.17). Conclusion: Although significant changes can occur in BMI, insulin sensitivity index, fasting blood sugar, and T3 in short-time follow-up after bariatric surgery, significant TSH and FreeT4 changes may need longer follow-ups.

Associations of TSH, free T3, free T4, and conversion ratio with incident hypertension: results from the prospective Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

Objective: To evaluate the association of TSH, free T3 (FT3), free T4 (FT4), and conversion (FT3:FT4) ratio values with incident hypertension. Materials and methods: The study included data from participants of the ELSA-Brasil study without baseline hypertension. Serum TSH, FT4 and FT3 levels, and FT3:FT4 ratio values were assessed at baseline, and incident hypertension (defined by blood pressure levels ≥ 140/90 mmHg) was estimated over a median of 8.2 years of follow-up. The risk of incident hypertension was evaluated considering a 1-unit increase in TSH, FT4, FT3, and conversion ratio values and after dividing these variables into quintiles for further analysis using Poisson regression with robust variance. The results are presented as relative risks (RR) and 95% confidence intervals (CIs) before and after adjustment for multiple variables. Results: The primary analysis incorporated data from 5,915 euthyroid individuals, and the secondary analysis combined data from all euthyroid individuals, 587 individuals with subclinical hypothyroidism, and 31 individuals with subclinical hyperthyroidism. The rate of incident hypertension was 28% (95% CI: 27%-29.3%). The FT4 levels in the first quintile (0.18-1.06 ng/dL) were significantly associated with incident hypertension (RR: 1.03, 95% CI: 1.01-1.06) at follow-up. The association between FT4 levels in the first quintile and incident hypertension was also observed in the analysis of combined data from euthyroid individuals and participants with subclinical thyroid dysfunction (RR: 1.04, 95% CI: 1.01-1.07). The associations were predominantly observed with systolic blood pressure levels in euthyroid individuals. However, in the combined analysis incorporating euthyroid participants and individuals with subclinical thyroid dysfunction, the associations were more pronounced with diastolic blood pressure levels. Conclusion: Low FT4 levels may be a mild risk factor for incident hypertension in euthyroid individuals and persons with subclinical thyroid dysfunction.

Determination of Frequency of Type 2 Deiodinase Thr92Ala Polymorphism (rs225014) in 131I-treated Differentiated Thyroid Cancer Patients Undertaking L-thyroxine (L-T4) Suppression Therapy.

Introduction: Type 2 deiodinase (DIO2) enzyme plays a vital role in peripheral T4 to T3 conversion and in the negative feedback regulation of pituitary thyroid-stimulating hormone (TSH) secretion. Thr92Ala polymorphism (rs225014) is a common single-nucleotide polymorphism (SNP) that lowers DIO2 activity and is associated with diverse physiological disorders. Differentiated thyroid cancer (DTC) patients are given L-T4 therapy after total thyroidectomy and 131I treatment to suppress TSH levels. Aim: The aim of the study was to determine the frequency of rs225014 in DTC patients and to investigate its effect on the thyroid function tests (TFTs) and L-T4 dose required to suppress TSH levels. Materials and Methods: The study included a DTC patient group and a control group. TFTs were estimated by RIA/IRMA kits. Genomic DNA of all the subjects was screened for rs225014 SNP by polymerase chain reaction. Results: The frequency of Thr/Thr (wild type), Thr/Ala (heterozygous mutant), and Ala/Ala (homozygous mutant) genotypes in the DTC patients' group was 0.21, 0.52, and 0.27, respectively. T3 levels and T3/T4 ratio were significantly low in the Ala/Ala genotype in the DTC group indicating impaired DIO2 activity. L-T4 dose requirement to suppress TSH levels in the DTC patients harboring rs225014 SNP was not statistically different from the wild-type genotype. Conclusion: The SNP rs225014 was observed to be associated with T3 and T3/T4 ratio but not with the L-T4 dose in DTC harboring SNP suggesting the presence of a compensatory pathway to overcome DIO2 impairment. However, it is essential to study the genetic makeup of DTC patients showing reduced response to TSH suppression to enable quicker decision-making in the implementation of personalized L-T4 dose to prevent any adverse effects.

Effect of Laparoscopic Sleeve Gastrectomy on Thyroid Function Tests and Levothyroxine Doses in People With Obesity.

INTRODUCTION: We investigated how laparoscopic sleeve gastrectomy (LSG) affected serum levels of thyroid-stimulating hormone (TSH), free thyroxine (FT4), and free triiodothyronine (FT3) in obese patients with hypothyroidism. We additionally examined whether the dose of levothyroxine decreases as a result of weight loss in this study. MATERIALS AND METHODS: Fifty-one people with obesity who received levothyroxine treatment for hypothyroidism and underwent LSG between January 2017 and January 2023 were retrospectively examined. Weight, body mass index (BMI), TSH, FT4, FT3, weekly levothyroxine dose changes, and weight-adjusted levothyroxine doses before surgery and the sixth month after surgery were compared. RESULTS: Among the 51 patients included in this study, 50.98% ceased the use of levothyroxine, and nearly half (41.18%) required an adjustment of their levothyroxine dose during the follow-up period (sixth month). Notably, the total weekly dose of levothyroxine (mcg) decreased in the sixth month following surgery (p<0.001). The weekly weight-adjusted dose (mcg/kg) decreased during the same time frame (p<0.001). The preoperative total weekly dose of levothyroxine, EWL% and absence of hyperlipidemia were found to be the independent predictors of the weight-adjusted weekly levothyroxine dose change (p<0.001, p=0.038, and p=0.044, respectively). CONCLUSIONS: Thyroid function tests in people with obesity can show improvement after LSG. LSG may reduce the weight-adjusted dose of levothyroxine at six months postoperatively and therefore patients should be monitored for possible levothyroxine dose readjustments based on weight loss.

The Impact of Physical Activity on Thyroid Health: Insights From Representative Data in Korea.

CONTEXT: Thyroid hormones are essential for energy metabolism related to thermogenesis and oxygen consumption. OBJECTIVE: This study evaluated the potential association of thyroid function including thyroid peroxidase antibodies (TPOAb) with physical activity in nationally representative data. DESIGN/SETTING/PARTICIPANTS: This retrospective cohort study used data from the Korean National Health and Nutrition Examination Survey between 2013 and 2015. Physical activity (PA) was assessed using metabolic equivalents based on the validated Korean version of the International Physical Activity Questionnaire Short Form. PA level was categorized into 3 groups of high, moderate, and low. Participants with abnormal thyroid function test, restricted activity, or previous history of thyroid disease were excluded in the study. RESULTS: A total of 5372 participants was finally selected. The free T4 level was lowest in the low PA group, while TSH was not significantly different among the groups. TPOAb titers increased in the following order: moderate PA, low PA, and high PA. After adjustment for confounding factors, moderate PA was associated with a high T4 level and a decrease in TSH and TPOAb with significance. However, there were no significant changes in free T4, TSH, or TPOAb titer in the high PA group. In a subanalysis, females with moderate PA showed a significant decrease in TSH and TPOAb. In both males and females, insulin sensitivity was increased with moderate PA. In obese participants, TSH negatively correlated with PA, and free T4 levels decreased in the low PA. The sensitivity to thyroid hormone did not differ in our study. CONCLUSION: The present study found an association between thyroid function and moderate PA. Therefore, moderate-intensity PA should be recommended to improve thyroid function.

MacroTSH: still a big problem for clinicians and clinical biochemists: lessons from a case report.

MacroTSH still interferes with TSH assays. We present here a case report illustrating the difficulties that can arise in such conditions and attempt to discuss the steps involved in diagnosis.

Protective effect of thyroid and restores of ovarian function of Buzhong Yiqi granule on experimental autoimmune thyroiditis in female rats.

OBJECTIVE: To observe the effects of Buzhong Yiqi granule on thyroid function and ovarian function in rats with experimental autoimmune thyroiditis (EAT). METHODS: EAT model was replicate by using the method of mixing and injecting porcine thyroglobulin with Freund's adjuvant and high iodine. Rats were randomly divided into normal control (NC) group, EAT model (EAT) group, selenium yeast (PC) group, low dose Buzhong Yiqi (BZYQ-L) group, medium dose Buzhong Yiqi (BZYQ-M) group and high dose Buzhong Yiqi (BZYQ-H) group. After two months of drug intervention according to dosage, enzyme-linked immunosorbent assay (ELISA) was used to measure the levels of free triiodothyronine (FT3), free thyroxine (FT4), thyroid-stimulating hormone (TSH), anti-thyroid peroxidase antibody (TPOAb), thyroglobulin antibody (TGAb) in peripheral blood of rats. The pathological changes of rat thyroid tissues were observed under light microscope with HE staining; ELISA was used to determine estradiol (E2), follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone (T), anti-müllerian hormone (AMH), and the pathological changes of rat ovarian tissues were observed under light microscope with hematoxylin and eosin staining. RESULTS: Compared with the NC group, BZYQ granule improved the thyroid and ovarian tissue morphology, and the levels of TPOAb, TGAb and TSH in the model group rats significantly increased (P < 0.05), the thyroid tissue was severely destroyed, the levels of E2, FSH, LH, T, AMH significantly increased (P < 0.05), and the ovary exhibited polycystic changes; Compared with the model group, TSH level in the BZYQ-L group rats decreased (P < 0.05), FSH, T, AMH levels decreased (P < 0.05), in the BZYQ-M group TPOAb, TSH levels decreased (P < 0.05), FSH, LH, T, AMH levels significantly decreased (P < 0.05), BZYQ-H group TPOAb, TGAb, TSH levels significantly decreased (P < 0.05), FSH, LH, T, AMH levels significantly decreased (P < 0.05), with the greatest improvement and significantly better than selenium yeast group (P < 0.05). CONCLUSIONS: BZYQ granule could regulate the thyroid function of EAT rats, reduce thyroid antibody titers, then act on the ovarian function, regulate hormone disorders, and alleviate the pathological damage of rat's ovarian tissues. The effect of high dose Buzhong Yiqi granule is the best.

Risk Factors for Thyroid Dysfunction in Pregnancy: An Individual Participant Data Meta-Analysis.

Background: International guidelines recommend targeted screening to identify gestational thyroid dysfunction. However, currently used risk factors have questionable discriminative ability. We quantified the risk for thyroid function test abnormalities for a subset of risk factors currently used in international guidelines. Methods: We included prospective cohort studies with data on gestational maternal thyroid function and potential risk factors (maternal age, body mass index [BMI], parity, smoking status, pregnancy through in vitro fertilization, twin pregnancy, gestational age, maternal education, and thyroid peroxidase antibody [TPOAb] or thyroglobulin antibody [TgAb] positivity). Exclusion criteria were pre-existing thyroid disease and use of thyroid interfering medication. We analyzed individual participant data using mixed-effects regression models. Primary outcomes were overt and subclinical hypothyroidism and a treatment indication (defined as overt hypothyroidism, subclinical hypothyroidism with thyrotropin >10 mU/L, or subclinical hypothyroidism with TPOAb positivity). Results: The study population comprised 65,559 participants in 25 cohorts. The screening rate in cohorts using risk factors currently recommended (age >30 years, parity ≥2, BMI ≥40) was 58%, with a detection rate for overt and subclinical hypothyroidism of 59%. The absolute risk for overt or subclinical hypothyroidism varied <2% over the full range of age and BMI and for any parity. Receiver operating characteristic curves, fitted using maternal age, BMI, smoking status, parity, and gestational age at blood sampling as explanatory variables, yielded areas under the curve ranging from 0.58 to 0.63 for the primary outcomes. TPOAbs/TgAbs positivity was associated with overt hypothyroidism (approximate risk for antibody negativity 0.1%, isolated TgAb positivity 2.4%, isolated TPOAb positivity 3.8%, combined antibody positivity 7.0%; p < 0.001), subclinical hypothyroidism (risk for antibody negativity 2.2%, isolated TgAb positivity 8.1%, isolated TPOAb positivity 14.2%, combined antibody positivity 20.0%; p < 0.001) and a treatment indication (risk for antibody negativity 0.2%, isolated TgAb positivity 2.2%, isolated TPOAb positivity 3.0%, and combined antibody positivity 5.1%; p < 0.001). Twin pregnancy was associated with a higher risk of overt hyperthyroidism (5.6% vs. 0.7%; p < 0.001). Conclusions: The risk factors assessed in this study had poor predictive ability for detecting thyroid function test abnormalities, questioning their clinical usability for targeted screening. As expected, TPOAb positivity (used as a benchmark) was a relevant risk factor for (subclinical) hypothyroidism. These results provide insights into different risk factors for gestational thyroid dysfunction.

A literature review on the redundancy of additional thyroid function tests in neonates of mothers with hypothyroidism.

AIM: Newborn thyroid screening tests are carried out during the first days after birth in many parts of the world. The aim of this review was to assess whether additional thyroid function tests of neonates born to mothers with hypothyroidism are necessary to diagnose newborns with congenital hypothyroidism (CH) missed by the usual screening test. METHODS: A search in PubMed and Google Scholar databases was conducted for pertinent studies, using relevant keywords. All studies that were published in any language from 1 January 2000 to 30 June 2023 were included. Observational cohort studies were included in the analysis, while case reports and studies not referring to neonates were excluded. RESULTS: Thirteen studies were identified comprising more than 4400 infants with CH. Studies with the larger study populations recommended against additional testing in healthy infants of hypothyroid mothers. Similar were the results of some smaller retrospective studies. Few studies identified in total 16 infants with CH that were missed on neonatal screening without, though, a definite causative link between the mother's and the infant's thyroid dysfunction. CONCLUSION: Based on available data, additional thyroid function tests seem redundant in identifying undiagnosed cases of CH. Larger studies are needed to reach a definite conclusion.

Impact of metformin on hypothalamic-pituitary-thyroid axis activity in women with autoimmune and non-autoimmune subclinical hypothyroidism: a pilot study.

BACKGROUND: Metformin reduces plasma TSH levels if these levels are elevated. No study has investigated whether the hormonal effects of metformin are impacted by thyroid autoimmunity. The current study aimed to compare the effect of metformin on hypothalamic-pituitary-thyroid axis activity between subjects with mild hypothyroidism of different origins. METHODS: The study population consisted of two groups of women with prediabetes and mildly elevated TSH levels, matched by age, insulin sensitivity, TSH, and thyroid hormone levels. Group A included 26 women with autoimmune thyroiditis, while group B enrolled 26 individuals with hypothyroidism of non-autoimmune origin. Both groups were treated with metformin (2.55-3 g daily). Circulating levels of TSH, total and free thyroid hormones, glucose, insulin, prolactin, high-sensitivity C-reactive protein (hsCRP) and 25-hydroxyvitamin D, concentrations of thyroid antibodies, and structure parameters of thyroid homeostasis were assessed at baseline and 6 months later. RESULTS: All patients completed the study. At baseline, both groups differed in concentrations of thyroid peroxidase antibodies, thyroglobulin antibodies, hsCRP, and 25-hydroxyvitamin D. The drug reduced TSH and Jostel's index, with no difference between the study groups. The improvement in insulin sensitivity, observed in both groups, was more pronounced in group B than in group A. In women with autoimmune hypothyroidism, the drug increased SPINA-GT and decreased hsCRP levels. The remaining markers did not change throughout the study. CONCLUSIONS: The obtained results suggest that, despite differences in thyroid output, the impact of metformin on TSH levels is similar in hypothyroid women with and without thyroid autoimmunity.

The Combined Effect of Immune Checkpoint Inhibitors and Tyrosine Kinase Inhibitors on Thyroid Function.

Background: Recent successes with immune checkpoint inhibitors (ICIs) and tyrosine kinase inhibitors (TKIs) for the treatment of solid malignancies have paved the way for a new era of combined therapy. A common side effect seen with each of these classes of treatment is thyroid dysfunction, with rates estimated at 30-40% for TKI and 10-20% for ICI. However, little is known about the effect of combined ICI+TKI therapy on thyroid function. Therefore, this study evaluated the incidence, clinical features, and risk factors for developing thyroid abnormalities during ICI+TKI therapy and the relationship to cancer outcomes. Methods: We conducted a retrospective cohort study of patients treated with combination ICI+TKI cancer therapy at City of Hope Comprehensive Cancer Center from 2017 to 2023 who had pretreatment normal thyrotropin (TSH) levels. Primary analyses assessed the frequency, timing, and severity of thyroid function test abnormalities during ICI+TKI cancer therapy, and the requirement for thyroid hormone replacement. Secondary analyses evaluated risk factors for the development of thyroid dysfunction, including sex and drug regimen, and the association with cancer progression-free survival or overall survival. Univariable and multivariable models were used. Results: There were 106 patients who received ICI+TKI therapy with a median age of 63.5 years and a median follow-up of 12.8 months (interquartile range [IQR] 5.9-20.9). Notably, 63.2% (67/106) developed thyroid function abnormalities during ICI+TKI therapy, including 11 (10.4%) with hyperthyroidism, 42 (39.6%) with subclinical hypothyroidism (SCHypo), and 14 (13.2%) with overt hypothyroidism. The onset of thyroid dysfunction occurred at a median of 7 weeks (IQR 3.1-9.0) after start of ICI+TKI treatment for hyperthyroidism, 8.0 weeks (IQR 3.0-19.0) for SCHypo, and 8.1 weeks (IQR 5.9-9.1) for overt or worsening hypothyroidism. Hyperthyroidism resolved to hypothyroidism or normal TSH without intervention in all subjects, suggesting thyroiditis, and hypothyroidism was readily treated with thyroid hormone replacement. Conclusions: Thyroid dysfunction is a frequent adverse event in individuals treated with combination ICI+TKI therapy, with our data suggesting a rapid onset and higher incidence than previously seen with ICI or TKI therapy alone. Therefore, close monitoring of thyroid function during initial therapy and multidisciplinary care with endocrinology are recommended to facilitate early detection and initiation of thyroid hormone replacement in these patients.

TSH and FT4 Reference Interval Recommendations and Prevalence of Gestational Thyroid Dysfunction: Quantification of Current Diagnostic Approaches.

CONTEXT: Guidelines recommend use of population- and trimester-specific thyroid-stimulating hormone (TSH) and free thyroxine (FT4) reference intervals (RIs) in pregnancy. Since these are often unavailable, clinicians frequently rely on alternative diagnostic strategies. We sought to quantify the diagnostic consequences of current recommendations. METHODS: We included cohorts participating in the Consortium on Thyroid and Pregnancy. Different approaches were used to define RIs: a TSH fixed upper limit of 4.0 mU/L (fixed limit approach), a fixed subtraction from the upper limit for TSH of 0.5 mU/L (subtraction approach) and using nonpregnancy RIs. Outcome measures were sensitivity and false discovery rate (FDR) of women for whom levothyroxine treatment was indicated and those for whom treatment would be considered according to international guidelines. RESULTS: The study population comprised 52 496 participants from 18 cohorts. Compared with the use of trimester-specific RIs, alternative approaches had a low sensitivity (0.63-0.82) and high FDR (0.11-0.35) to detect women with a treatment indication or consideration. Sensitivity and FDR to detect a treatment indication in the first trimester were similar between the fixed limit, subtraction, and nonpregnancy approach (0.77-0.11 vs 0.74-0.16 vs 0.60-0.11). The diagnostic performance to detect overt hypothyroidism, isolated hypothyroxinemia, and (sub)clinical hyperthyroidism mainly varied between FT4 RI approaches, while the diagnostic performance to detect subclinical hypothyroidism varied between the applied TSH RI approaches. CONCLUSION: Alternative approaches to define RIs for TSH and FT4 in pregnancy result in considerable overdiagnosis and underdiagnosis compared with population- and trimester-specific RIs. Additional strategies need to be explored to optimize identification of thyroid dysfunction during pregnancy.

Approach to the Patient With Raised Thyroid Hormones and Nonsuppressed TSH.

Measurement of free thyroid hormones (THs) and thyrotropin (TSH) using automated immunoassays is central to the diagnosis of thyroid dysfunction. Using illustrative cases, we describe a diagnostic approach to discordant thyroid function tests, focusing on entities causing elevated free thyroxine and/or free triiodothyronine measurements with nonsuppressed TSH levels. Different types of analytical interference (eg, abnormal thyroid hormone binding proteins, antibodies to iodothyronines or TSH, heterophile antibodies, biotin) or disorders (eg, resistance to thyroid hormone ß or α, monocarboxylate transporter 8 or selenoprotein deficiency, TSH-secreting pituitary tumor) that can cause this biochemical pattern will be considered. We show that a structured approach, combining clinical assessment with additional laboratory investigations to exclude assay artifact, followed by genetic testing or specialized imaging, can establish a correct diagnosis, potentially preventing unnecessary investigation or inappropriate therapy.

One children's hospital planning and development process to adhere to the FDA recommendation that babies and young children undergo thyroid function testing after receiving an injection of iodine-containing contrast media for medical imaging.

The United States (US) Food and Drug Administration (FDA) has issued multiple statements and guidelines since 2015 on the topic of thyroid function testing in babies and children through 3 years old after receiving iodinated contrast media for medical imaging exams. In April 2023, the FDA adjusted this recommendation to target babies and young children younger than 4 years of age who have a history of prematurity, very low birth weight, or underlying conditions which affect thyroid gland function, largely in response to solid arguments from expert statements from the American College of Radiology (ACR) which is endorsed by the Society for Pediatric Radiology (SPR), Pediatric Endocrinology Society (PES), and the Society for Cardiovascular Angiography & Intervention (SCAI). Herein we describe our approach and development of a clinical care guideline along with the steps necessary for implementation of the plan including alterations in ordering exams requiring iodinated contrast media, automatic triggering of lab orders, reporting, and follow-up, to address the 2022 FDA guidance statement to monitor thyroid function in children after receiving iodinated contrast media. The newly implemented clinical care guideline at Ann and Robert H. Lurie Children's Hospital of Chicago remains applicable following the 2023 updated recommendation from the FDA. We will track patients less than 3 months of age who undergo thyroid function testing following computed tomography (CT), interventional radiology, and cardiac catheterization exams for which an iodinated contrast media is administered as a clinical care quality initiative.

Interference against a newly labeled substance with ruthenium sulfonate complexes showing discrepant thyroid function test results.

We report here two patients exhibiting a combination of falsely elevated serum levels of free thyroxine (FT4), free triiodothyronine (FT3), and thyrotropin receptor antibodies (TRAb), measured using Elecsys assay kits (Roche Diagnostics GmbH). The first patient was a 74-year-old man misdiagnosed with Graves' disease and treated with methimazole. The second patient was a 48-year-old woman whose serum FT4 and FT3 concentrations were found to be high during a blood test. These patients denied taking biotin or any other supplements. Further detailed examination, including a heterophilic blocking tube test, revealed the presence of serum antibodies. The abnormal reactions were observed only using the improved assay kits using ruthenium (Ru) sulfonate instead of Ru as a chemiluminescent agent. Therefore, serum antibodies to the Ru sulfonate complex caused the pseudo-high levels of FT4, FT3, and TRAb. To our knowledge, this is the first report showing that antibodies to the Ru sulfonate complex in the electrochemiluminescence immunoassay can cause falsely elevated levels of the combination, leading to discrepant thyroid function test results. We emphasize that in cases of abnormal test results, alternative assay methods should be considered for further examination; unusual test results should not be impulsively interpreted, even when using revised assay kits.

Associations of TSH, free T3, free T4, and conversion ratio with incident hypertension: results from the prospective Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

ABSTRACT Objective: To evaluate the association of TSH, free T3 (FT3), free T4 (FT4), and conversion (FT3:FT4) ratio values with incident hypertension. Materials and methods: The study included data from participants of the ELSA-Brasil study without baseline hypertension. Serum TSH, FT4 and FT3 levels, and FT3:FT4 ratio values were assessed at baseline, and incident hypertension (defined by blood pressure levels ≥ 140/90 mmHg) was estimated over a median of 8.2 years of follow-up. The risk of incident hypertension was evaluated considering a 1-unit increase in TSH, FT4, FT3, and conversion ratio values and after dividing these variables into quintiles for further analysis using Poisson regression with robust variance. The results are presented as relative risks (RR) and 95% confidence intervals (CIs) before and after adjustment for multiple variables. Results: The primary analysis incorporated data from 5,915 euthyroid individuals, and the secondary analysis combined data from all euthyroid individuals, 587 individuals with subclinical hypothyroidism, and 31 individuals with subclinical hyperthyroidism. The rate of incident hypertension was 28% (95% CI: 27%-29.3%). The FT4 levels in the first quintile (0.18-1.06 ng/dL) were significantly associated with incident hypertension (RR: 1.03, 95% CI: 1.01-1.06) at follow-up. The association between FT4 levels in the first quintile and incident hypertension was also observed in the analysis of combined data from euthyroid individuals and participants with subclinical thyroid dysfunction (RR: 1.04, 95% CI: 1.01-1.07). The associations were predominantly observed with systolic blood pressure levels in euthyroid individuals. However, in the combined analysis incorporating euthyroid participants and individuals with subclinical thyroid dysfunction, the associations were more pronounced with diastolic blood pressure levels. Conclusion: Low FT4 levels may be a mild risk factor for incident hypertension in euthyroid individuals and persons with subclinical thyroid dysfunction.

Exploring the Association between Thyroid Function and Frailty: Insights from Representative Korean Data.

BACKGRUOUND: This study investigates the association between thyroid function and frailty in the old patients using representative data. METHODS: The study was conducted using data from the Korea National Health and Nutrition Examination Survey conducted from 2013 to 2015. The study population included 2,416 participants aged 50 years and older with available thyroid function test data. Frailty assessment was performed using the Fried frailty phenotype. The prevalence of frailty was analyzed across different thyroid diseases and thyroid function parameters. RESULTS: The significant association between thyroid dysfunction and frailty was observed in overt hyperthyroidism and subclinical hyperthyroidism. After adjusting for various factors, the association between thyroid dysfunction and frailty remained significant. On the other hand, overt hypothyroidism did not show a significant association with frailty in the adjusted analysis. For individuals with overt hyperthyroidism and subclinical hyperthyroidism, higher levels of free thyroxine (FT4) were significantly associated with an increased risk of frailty (aOR >999; 95% CI, >999 to 999). Among individuals with overt hypothyroidism, lower level of FT4 levels and high thyrotropin (TSH) levels showed a significant association with frailty risk (FT4: aOR, <0.01; TSH: aOR, 999). In participants with subclinical hypothyroidism, there were no significant associations between parameters for thyroid and frailty risk. CONCLUSION: These findings suggest that thyroid dysfunction, particularly overt hyperthyroidism and subclinical hyperthyroidism, may be associated with an increased risk of frailty in the old patients.