Thyroid-stimulating Hormone Testing Research Articles

Current utility of first-line FT4 and TSH in screening for central hypothyroidism.

Thyroid testing strategies vary across laboratories. First-line combined thyroid stimulating hormone (TSH) and freeT4 (FT4) have historically been preferred by many laboratories as this detects individuals with undiagnosed central hypothyroidism who can be missed with a first-line TSH-only strategy. However, an up-to-date evaluation of the utility of this approach is lacking. We investigated the clinical utility of first-line TSH and FT4 in the detection of central hypothyroidism in current day practice. The All-Wales laboratory information system was queried to identify thyroid function tests in patients aged ≥16 years with decreased FT4 and inappropriate TSH (low-FT4). The 1-year incidence of low-FT4 was determined using mid-year population data. Clinical information of patients with low-FT4 was reviewed to determine causes of low-FT4 and the incidence of central hypothyroidism. The incidence of low-FT4 varied according to FT4 assay method (range: 98-301 cases/100,000 population/year). Fifteen new cases of central hypothyroidism were detected in two health boards, equivalent to 2 cases/100,000 population/year. Positive predictive value of low-FT4 for central hypothyroidism was 2%-4%. In a cross-section of primary care patients, low-FT4 was detected in 0.5% of all thyroid tests with assay-related differences in detection rates. Although low-FT4 is a common laboratory finding, the incidence of central hypothyroidism remains rare. With the currently increased rates of thyroid testing and increased use of medications that decrease FT4, low-FT4 has a much lower predictive value for central hypothyroidism than previously reported. Thyroid screening strategies will need to balance the yield from first line TSH and FT4 testing with the cost of investigating individuals with non-pathological laboratory abnormalities.

Correlation Between Thyroid-Stimulating Hormone (TSH) and Liver Function Test Values in North Karnataka Patients Admitted to a Tertiary Care Hospital

Correlation Between Thyroid-Stimulating Hormone (TSH) and Liver Function Test Values in North Karnataka Patients Admitted to a Tertiary Care Hospital

Association of Vitiligo with ABO/Rh System and its Influence on Thyroid Stimulating Hormone and Vitamin D

This study was conducted to determine if there is a relationship between vitiligo and ABO blood groups, the Rhesus (Rh) factor, thyroid stimulating hormone (TSH) and vitamin D. For vitiligo analysis, two hundred subjects participated in this study, 100 vitiligo patients and 100 control cases (without vitiligo). ABO blood grouping and Rh typing were tested by a slide method. TSH testing involved 80 vitiligo patients and 80 controls (without vitiligo) and the hormone was analyzed by separating the serum in a centrifuge for two minutes and the results were obtained by Beckman fully automatic analyzer. For vitamin D, 50 vitiligo patients and 50 healthy people (without vitiligo) were included. The data on vitamin D were obtained from private laboratory services. Statistical analysis was performed using IBM SPSS version 26. P<0.05 was considered significant. Most patients with vitiligo had a significantly lower level of serum vitamin D compared with controls (p-value < 0.05), while no statistically significant difference in TSH serum levels between vitiligo cases and controls, was found (p-value > 0.05). Furthermore, despite showing that subjects with blood group O are more susceptible to vitiligo as compared to other groups, there was no significant association of vitiligo with ABO blood groups (p-value > 0.05). Similarly, the incidence of Rh positive and Rh negative was not statistically different between the two groups (p-value > 0.05). This study showed that vitiligo patients are often vitamin D deficient. This study highlights the need to evaluate vitamin D status in vitiligo patients to improve the level of skin pigment loss. It remains unknown whether vitamin D deficiency causes vitiligo. However, a collection of larger sample sizes of different ethnicities should be required to achieve a precise conclusion.

Correlation of Thyroid Stimulating hormone and Liver function test in Hypothyroid and Euthyroid subjects

Correlation of Thyroid Stimulating hormone and Liver function test in Hypothyroid and Euthyroid subjects

Identification of important symptoms and diagnostic hypothyroidism patients using machine learning algorithms

Background: Hypothyroidism is one of the most common endocrine diseases. It is, however, usually challenging for physicians to diagnose due to non-specific symptoms. The usual procedure for diagnosis of Hypothyroidism is a blood test. In recent years, machine learning algorithms have proved to be powerful tools in medicine due to their diagnostic accuracy. In this study, we aim to predict and identify the most important symptoms of Hypothyroidism using machine learning algorithms. Method: In this cross-sectional, single-center study, 1296 individuals who visited an endocrinologist for the first time with symptoms of Hypothyroidism were studied, 676 of whom were identified as patients through thyroid-stimulating hormone (TSH) testing. The outcome was binary (with Hypothyroidism /without Hypothyroidism). In a comparative analysis, random forest (RF), decision tree (DT), and logistic regression (LR) methods were used to diagnose primary Hypothyroidism. Results: Symptoms such as tiredness, unusual cold feeling, yellow skin (jaundice), cold hands and feet, numbness of hands, loss of appetite, and weight Hypothyroidism gain were recognized as the most important symptoms in identifying Hypothyroidism. Among the studied algorithms, RF had the best performance in identifying these symptoms (accuracy = 0.83, kappa = 0.46, sensitivity = 0.88, specificity = 0.88). Conclusions: The findings suggest that machine learning methods can identify Hypothyroidism patients who show relatively simple symptoms with acceptable accuracy without the need for a blood test. Greater familiarity and utilization of such methods by physicians may, therefore, reduce the expense and stress burden of clinical testing.

Inappropriate laboratory test utilization in outpatient tertiary care: Implications for value-based healthcare.

To assess the rate of inappropriate repetition of laboratory testing and estimate the cost of such testing for thyroid stimulating hormone (TSH), total cholesterol, vitamin D, and vitamin B12 tests. A retrospective cohort study was carried out in the Family Medicine and Polyclinic Department at King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia. Clinical and laboratory data were collected between 2018-2021 for the 4 laboratory tests. The inappropriate repetition of tests was defined according to international guidelines and the costs were calculated using the hospital prices. A total of 109,929 laboratory tests carried out on 23,280 patients were included in this study. The percentage of inappropriate tests, as per the study criteria, was estimated to be 6.1% of all repeated tests. Additionally, the estimated total cost wasted amounted to 2,364,410 Saudi Riyals. Age exhibited a weak positive correlation with the total number of inappropriate tests (r=0.196, p=0.001). Furthermore, significant differences were observed in the medians of the total number of inappropriate tests among genders and nationalities (p<0.001). The study identified significantly high rates of inadequate repetitions of frequently requested laboratory tests. Urgent action is therefore crucial to overcoming such an issue.

Lack of Association Between Depression and Subclinical Hypothyroidism in Adolescents Presenting for Routine Physical Examinations.

There are conflicting results in the existing studies regarding the association between depression and subclinical hypothyroidism in adolescents. Subclinical hypothyroidism is defined as elevated thyroid stimulating hormone (TSH) levels above the reference range without signs or symptoms of hypothyroidism. The focus of this study is to determine whether there is any association between depression and subclinical hypothyroidism, (as defined by the serum TSH levels) in a population of healthy adolescents. Quantitative-based cross-sectional study of a representative subset of the adolescent population. We carried out a cross-sectional study to determine the association between major depressive disorder (MDD) and subclinical hypothyroidism, in adolescents presenting for annual physical examinations during the peak period of the COVID-19 pandemic in the USA, a period deemed high for adolescent depression. All the adolescents were screened for depression by the PHQ-9 screening tool and had their TSH measured. Of the 304 subjects analyzed, 179 (58.88%) were minimally or not depressed according to the Patient Health Questionnaire (PHQ-9) screening tool (mean PHQ 1.80 ± 1.49). 70 (23.03%) had mild depression (mean PHQ 6.59 ± 1.46), 50 (16.45%) had moderate depression (mean PHQ 13.70 ± 2.75), and 5 (1.64%) had severe depression (mean PHQ 21.40 ± 1.67). Mean TSH values were 1.93 ± 0.99, 1.77 ± 1.05, 2.10 ± 0.98, and 1.57 ± 0.32 mIU/L, respectively in the four groups. All values were within the recommended range of 0.50 to 4.30 mIU/L, without statistically significant inter-group differences. We conclude that there is no statistically significant association between depression and subclinical hypothyroidism, in a population of adolescents presenting for physical examinations, and if the screening for depression by the PHQ-9 tool indicates depression, a screening TSH test for subclinical hypothyroidism is not justified.

Elevated TSH Levels: A Database Study of General Practitioners’ Course of Action

ObjectiveTo investigate general practitioners’ course of action after detection of elevated thyroid stimulating hormone (TSH) levels regarding repeat testing, direct levothyroxine replacement, or neither. MethodsWe conducted a retrospective study of adults without prior evidence of thyroid disease and with a first detection of elevated TSH levels from January 1, 2015, to December 31, 2020, using data from electronic medical records of a Swiss primary care database. We determined the occurrence of either repeat TSH testing or direct levothyroxine initiation in primary care during 12-month follow-up and determined associations with demographic and clinical factors. ResultsOf the 1 591 patients included (median age 65 years, 64.4% female, median TSH 5.7 mIU/L), 34.3% received repeat TSH testing and 12.4% received direct levothyroxine replacement in primary care during follow-up. Repeat TSH testing showed the strongest association with overt hypothyroidism and was more common among patients with high primary care utilization and among patients aged 40-64 years compared to patients aged <40 years. Direct levothyroxine initiation was more likely for TSH levels >7 mIU/L, overt hypothyroidism, female patients, and nonurban practices. ConclusionsWhile the degree of thyroid dysfunction was the main driver of follow-up, we identified important gaps in the primary care-based monitoring of elevated TSH levels in young patients and in patients with infrequent consultations. We also observed potential overtreatment of women and patients in nonurban areas. Our findings highlight the need for standardization and dissemination of guidelines for the management of elevated TSH levels among general practitioners.

Monitoring Thyrotropin in Veterans With Thyroid Nodules.

After the initial thyroid nodule diagnosis, a patient's thyrotropin is often monitored. However, the American Thyroid Association guidelines do not offer recommendations for follow-up thyrotropin testing for patients with thyroid nodules who have no history of conditions or known medications that affect thyroid hormone levels. At the Veterans Affairs Dayton Healthcare System in Ohio, we conducted a retrospective chart review from January 2010 to December 2016 of 100 patients diagnosed with ≥ 1 thyroid nodule on imaging studies who had normal blood thyrotropin at the time of nodule diagnosis. The thyrotropin value was studied at and after diagnosis. A 95% CI was determined for the true population rate of patients with an abnormal thyrotropin at their most recent testing. χ2 tests for categorical variables and independent sample t tests for continuous variables were used to compare the abnormal and normal most recent thyrotropin groups. One hundred patients (male [83%], White race [82%]) with normal thyrotropin at nodule diagnosis had thyrotropin monitoring for a mean (SD) of 5.7 (2.5) years. Six of 100 patients (6%; 95% CI, 2.5%-12.7%) developed abnormal thyrotropin levels in a mean (SD) of 6.9 (3.1) years. When comparing the 6 patients with abnormal thyrotropin vs the 94 with normal thyrotropin, there were no significant differences in sex (P = .99), race (P = .55), age at diagnosis (P = .12), initial thyrotropin level (P = .24), most recent thyrotropin level (P = .98), or time from diagnosis to most recent thyrotropin level (P = .23). This study found no significant change in thyrotropin levels over time in patients with thyroid nodules and no history of medical conditions or medications known to affect thyrotropin levels. Monitoring thyrotropin over time may not be required in these patients. More studies are needed to provide additional data on thyrotropin monitoring for thyroid nodules so that clinicians can make evidence-based decisions.

Trends and Components of Thyroid Status Evaluation in Commercially Insured Adults in the United States, 2006-2020.

Thyroid-stimulating hormone (TSH) is one of the most ordered laboratory tests. Determine trends of TSH testing rates and components of thyroid function testing. This was a retrospective analysis of adults 18-64 years old without evidence of thyroid disease with at least 365 days of continuous enrollment between 2006 and 2020 in the IBM MarketScan Claims Database. The main outcome measures were trends of TSH tests/1000 eligible patient-months stratified by age, sex, and region and composition of thyroid function testing. Among 67 353 280 patients meeting eligibility criteria, we identified 25 606 518 TSH tests and 15 138 211 patients with ≥1 TSH test. Patients contributing an episode of TSH testing were most commonly 45-54 years old (29.8%) and female (63.6%). TSH testing rates remained consistent throughout the study period with 11.4 and 11.7 TSH tests/1000 person-months in the first and last study months, respectively (mean 12.2 TSH tests/1000 person-months). TSH testing rates dropped sharply in the spring of 2020 (4.2 TSH tests/1000 person-months). Females showed a nearly 2-fold higher rate of TSH testing than males (16.1 TSH tests/1000 person-months vs 8.6 TSH tests/1000 person-months). TSH testing rates increased with age (8.2 TSH tests/1000 person-months among individuals 18-34 years old vs 15.4 TSH tests/1000 person-months among individuals 55-64 years old). No difference in TSH testing rates was noted between regions. Thyroid function testing episodes included only TSH in most cases (70.8%). TSH testing rates among commercially insured individuals without known thyroid disease appears stable over time, with higher frequency in females and with increasing age.

Polyethylene glycol thyroid-stimulating hormone (PEG-TSH) testing in the management of pediatric thyroid dysfunction.

The polyethylene glycol (PEG) methodology is used for investigating incongruities in laboratory assays, such as thyroid-stimulating hormone (TSH) measurements. The aim of the study is to investigate the practical application of PEG-TSH testing in cases of discrepancies between elevated TSH and normal free thyroxine (FT4) levels. A real-life observational study conducted in a tertiary medical center. The hospital's electronic database was queried for TSH tests performed in pediatric patients between 2015 and 2023. Of those, PEG-TSH were identified. Patients' clinical and biochemical characteristics and PEG-TSH-guided management were assessed. In total, 2949 TSH tests were performed in 891 children and adolescents for various indications. Among them were 61 (2.1%) PEG-TSH results, mean age 7.1 ± 5.3 years, of 38 patients (4.3%), comprised of 16 with congenital hypothyroidism, 16 with subclinical hypothyroidism, and 6 with Hashimoto thyroiditis. Both the TSH and the PEG-TSH levels of patients with congenital hypothyroidism were higher than those of the other two groups (P = 0.021 and P = 0.009, respectively), with no group differences in FT4 levels. Spearman's correlation analysis revealed a strong association between TSH and PEG-TSH levels: r = 0.871, P < 0.001. In nearly one-half of the cases, clinical decisions made by clinicians (decreasing the dose or not initiating L-thyroxine treatment) were affected by the PEG-TSH results. Our findings support PEG-TSH testing for determining appropriate TSH levels and avoid unnecessary thyroid hormone treatment among children and adolescents. We propose the suitability of managing their clinical condition based upon age-appropriate clinical parameters and FT4 levels when their PEG-TSH levels are within the normal range.

SAT467 Monitoring TSH Over Time May Not Be Necessary in Patients With Thyroid Nodules

Abstract Disclosure: S. Kaul: None. A. Gupta: None. Introduction: A substantial number of patients with thyroid nodules receive monitoring of blood thyroid stimulating hormone (TSH) levels after the initial diagnosis. There is not enough literature supporting long-term monitoring of blood TSH levels in these patients with thyroid nodules. The objective of this study was to evaluate the change in blood TSH level in patients with known thyroid nodules over time and to determine if repeat blood TSH testing is required in these patients. We hypothesized that monitoring of blood TSH level is not warranted in patients with thyroid nodules in the absence of a history of medical conditions or medications that are known to affect thyroid hormone levels. Methods: We studied 100 patients aged 18 to 99 years at the Dayton VA Medical Center with at least one thyroid nodule on imaging studies from January 2010 to December 2016 with normal blood TSH level at time of the diagnosis of the thyroid nodule. Subjects with abnormal thyroid hormone level, history of hot thyroid nodule, autoimmune thyroid disease (on imaging or blood work), thyroid or pituitary surgery, radioactive iodine treatment, neck irradiation, or usage of thyroxine or any other medications known to affect thyroid hormone levels were excluded. Blood TSH level at the time of diagnosis of thyroid nodule and after were retrospectively studied and analyzed for 100 subjects. Normal blood TSH level range at time of diagnosis was noted to be 0.35-5.50 uIU/mL or 0.35-4.00 uIU/mL depending on the assay method used. Normal repeat blood TSH level range was noted to be 0.35-5.50 uIU/mL, 0.35-4.00 uIU/mL, or 0.55-4.78 uIU/mL depending on the assay method used. Results: 100 subjects with normal blood TSH at the time of diagnosis of their thyroid nodule had blood TSH level monitoring for an average time period of 5.74 years. Out of the 100, six subjects (6%, 95% CI [2.52%, 12.73%]) developed an abnormal blood TSH level in a mean time period of 6.94 years. One subject’s initial blood TSH level increased from 3.38 uIU/mL to 7.76 uIU/mL after 8.52 years. This subject did not receive treatment with thyroxine. In the other five subjects, blood TSH level decreased to below normal range in a mean time period of 6.63 years and ranged from 0.25-0.52 uIU/mL. Blood TSH level remained within normal range for 94 subjects in a mean time period of 5.67 years. Conclusion: Monitoring of blood TSH level over time may not be required in most patients with thyroid nodules in the absence of symptoms, medical conditions, or medications that are known to affect thyroid hormone levels. Presentation Date: Saturday, June 17, 2023

FRI485 High Interlaboratory Variability In Free Thyroxine Measurement Indicates Need For Method Standardization

Abstract Disclosure: A. Ribera: None. U. Danilenko: None. O. Sugahara: None. L. Collins: None. T. Buchannan: None. N. Vazquez: None. F. Pokuah: None. D. Wirtz: None. L. Zhang: None. A.N. Lyle: None. H.W. Vesper: None. Thyroid function tests are critical to diagnose diseases of the thyroid. Concerns about the accuracy and reliability of thyroid function tests, especially free thyroxine (FT4), have been stated by the clinical laboratory community for many years. In response to these concerns, the CDC Clinical Standardization Program (CSP) has created a standardization program for FT4 based on the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) reference system and is partnering with IFCC to standardize FT4 and harmonize TSH testing globally. As part of this program, CDC developed an accurate and sensitive reference measurement procedure (RMP) to assign reference values to individual donor sera. Assay manufacturers and research and clinical laboratories can use these sera to assess the analytical performance of their measurements, and monitor analytical performance over time. To obtain initial information about the analytical performance of FT4 and TSH measurements, an interlaboratory study among commercial assays and laboratory developed test was conducted. A panel of 40 blinded, fresh-frozen single donor patient serum samples with FT4 concentration ranging between 11-32 pmol/L concentrations was measured by participants and compared to the results obtained by CDC RMP for FT4. In addition, commercial assay manufacturers were asked to measure thyroid-stimulating hormone (TSH). Results from sixteen commercial assays and four laboratory developed test (LDT) participated. Preliminary results indicate a negative mean bias for all commercial FT4 assays ranging from -34.46% to -5.08%. Some of the assays agreed more closely to the RMP than others (four assays had mean bias over -25%). An equilibrium dialysis mass spectrometry-based assays had mean biases ranging from -8.86% to - 1.72% agreeing well with RMP. The data suggest that the observed bias can be effectively minimized through recalibration to the RMPs operated by the CDC CSP and the IFCC reference laboratory network. The mean TSH concentrations ranged from 0.34 to 21.56 uIU/mL with mean %CV of 11.42% (95%CI 8.07%-14.76%) suggesting good agreement between various platforms. Findings from this study will be used to customize CDC’s protocols and procedures for standardizing FT4 measurements. Presentation: Friday, June 16, 2023

Quantitative Detection of Thyroid-Stimulating Hormone in Patient Samples with a Nanomechanical Single-Antibody Spectro-Immunoassay.

Functional disorders of the thyroid remain a global challenge and have profound impacts on human health. Serving as the barometer for thyroid function, thyroid-stimulating hormone (TSH) is considered the single most useful test of thyroid function. However, the prevailing TSH immunoassays rely on two types of antibodies in a sandwich format. The requirement of repeated incubation and washing further complicates the issue, making it unable to meet the requirements of the shifting public health landscape that demands rapid, sensitive, and low-cost TSH tests. Herein, a systematic study is performed to investigate the clinical translational potential of a single antibody-based biosensing platform for the TSH test. The biosensing platform leverages Raman spectral variations induced by the interaction between a TSH antigen and a Raman molecule-conjugated TSH antibody. In conjunction with machine learning, it allows TSH concentrations in various patient samples to be predicted with high accuracy and precision, which is robust against substrate-to-substrate, intra-substrate, and day-to-day variations. It is envisioned that the simplicity and generalizability of this single-antibody immunoassay coupled with the demonstrated performance in patient samples pave the way for it to be widely applied in clinical settings for low-cost detection of hormones, other molecular biomarkers, DNA, RNA, and pathogens.

Thyroid Stimulating Hormone Test and its Effect on the Human Body

Thyroid Stimulating Hormone Test and its Effect on the Human Body

Global prevalence of congenital hypothyroidism among neonates from 1969 to 2020: a systematic review and meta-analysis.

Little is known about the global prevalence of congenital hypothyroidism (CH), though it is known to vary across countries and time periods. This meta-analysis aims to estimate the global and regional prevalence of CH among births between 1969 and 2020. PubMed, Web of Sciences, and Embase databases were searched for relevant studies between January 1, 1975, and March 2, 2020. Pooled prevalence was calculated using a generalized linear mixed model, and expressed as a rate per 10,000 neonates. The meta-analysis involved 116 studies, which analyzed 330,210,785 neonates, among whom 174,543 were diagnosed with CH. The pooled global prevalence of CH from 1969 to 2020 was 4.25 (95% confidence interval (CI) 3.96-4.57). The geographic region with highest prevalence was the Eastern Mediterranean (7.91, 95% CI 6.09-10.26), where the prevalence was 2.48-fold (95% CI 2.04-3.01) that in Europe. The national income level with the highest prevalence was upper-middle (6.76, 95% CI 5.66-8.06), which was 1.91-fold (95% CI 1.65-2.22) that in high-income countries. Global prevalence of CH was 52% (95% CI 4-122%) higher in 2011-2020 than in 1969-1980, after adjusting for geographic region, national income level, and screening strategy. Conclusion: The global prevalence of CH increased from 1969 to 2020, which may reflect the implementation of national neonatal screening, neonatal testing for thyroid-stimulating hormone, and a lowering of the diagnostic level of this hormone. Additional factors are likely to be driving the increase, which should be identified in future research. What is Known: • Cumulated evidence had suggested that the occurrences of congenital hypothyroidism (CH) among newborns were varied in different countries.. • Up-trends of the birth prevalence of CH were observed in many European and American countries. What is New: • This is the first meta-analysis to estimate global and regional prevalence of CH among newborns. • The global prevalence of CH has increased by 127% since 1969. The Eastern Mediterranean has the highest prevalence and stands out with the most pronounced escalation in the prevalence of CH.

The Correlation between the First Trimester Combined Test Results and Thyroid Stimulating Hormone Levels as Well as Its Effect on Pregnancy Outcomes.

Determining the pregnancy outcomes with independent prognostic factors in the first trimester combined screening test and thyroid stimulating hormone (TSH) is a concern for practitioners. We aimed to evaluate the correlation between TSH and first trimester combined screening test levels and examine their effects on pregnancy outcomes in healthy pregnant women. A total of 349 pregnant women in Izmir Ataturk Training and Research Hospital, Turkey with normal TSH values in the first trimester between 2015 and 2020 were enrolled. Patients were divided into two groups as 274 and 75 patients according to TSH values with 2,5 as cut-off value; their birth weights and weeks were compared. Patients were also divided into three groups according to gestational weeks; their TSH values and combined tests were compared. When grouped based on the TSH threshold value (2.5uIU/ml), no significant relationship was found between the combined test parameters and TSH levels. In the combined test, after grouping according to the week of gestation, a negative correlation was observed between free beta-human chorionic gonadotropin (β-hCG) and TSH measured at 11 weeks (P=0.040, r=-0.189). A significant negative correlation was found between free β-hCG and newborn birth weight (P=0.032, r=-0.199), TSH and delivery time (P=0.011, r=-0.235). Free β-hCG and TSH levels could guide practitioners for birth weight and early delivery, respectively. Postponing the combined test for patients with elevated serum TSH levels to between the 12th and 13th weeks of gestation may reduce false positives.

Medical Management of Dental Abnormalities Related to Congenital Hypothyroidism in a Cat.

A 5-month-old intact male domestic shorthair cat presenting for routine vaccinations was diagnosed with congenital hypothyroidism. His primary presenting symptom was incomplete dentition with delayed dental eruption. Congenital hypothyroidism was confirmed by baseline thyroxine (T4), free T4, and thyroid-stimulating hormone testing. The cat was treated with oral thyroid hormone supplementation and 16 weeks after initiation of therapy the cat was clinically normal with age-appropriate dentition. No surgical intervention was necessary to achieve normal dental eruption.

Prevalence, causes, and impact of non-visualized pregnancy losses in a recurrent pregnancy loss population.

Does the occurrence of non-visualized pregnancy loss (NVPL) affect future reproductive outcomes in patients with recurrent pregnancy loss (RPL)? The number of previous NVPLs is a significant predictor of subsequent live birth in patients with RPL. The number of preceding miscarriages is a strong indicator for future reproductive outcomes. However, NVPL particularly has been sparsely addressed in previous literature. We performed a retrospective cohort study of 1981 patients attending a specialized recurrent pregnancy loss clinic (RPL) from January 2012 to March 2021. A total of 1859 patients met the inclusion criteria of the study and were included in the analysis. Patients with a history of RPL, defined as ≥2 pregnancy losses before 20 weeks gestation, who attended a specialized RPL clinic in a tertiary care center were included. Patients' evaluation included parental karyotyping, antiphospholipid antibodies screening, uterine cavity assessment with hysterosalpingography (HSG) or hysteroscopy, maternal thyroid stimulating hormone (TSH) testing, and serum hemoglobin A1C testing. Other investigations were performed only when indicated such as testing for inherited thrombophilias, serum prolactin, oral glucose tolerance test, and endometrial biopsy. Patients were divided into three groups; patients who experienced NVPLs only (pure NVPLs group), patients with only visualized pregnancy losses (pure VPLs group), and patients with history of both NVPLs and VPLs (mixed group). Statistical analysis was performed using Wilcoxon rank-sum tests for continuous variables and Fisher's exact tests for categorical variables. Significance was detected when P values <0.05. A logistic regression model was used to determine the impact of NVPLs and VPLs numbers on any live birth subsequent to the initial RPL clinic visit. The prevalence of patients with pure NVPLs, pure VPLs, and mixed losses was 14.7% (274/1859), 31.8% (591/1859), and 53.5% (994/1859), respectively. The prevalence of acquired and congenital uterine anomalies diagnosed by HSG or hysteroscopy was significantly different between pure NVPLs, pure VPLs, and mixed groups (16.8% versus 23.7% versus. 20.7%, respectively P = 0.05). There were no significant differences in the results of other RPL investigations or baseline demographics between the three groups. A logistic regression model controlling for maternal age at the initial RPL clinic visit and the follow-up duration showed that the numbers of NVPLs (odds ratio (OR): 0.77, CI: 0.68-0.88) and VPLs (OR: 0.75, CI: 0.64-0.86) are strong predictors for subsequent live births after the initial RPL clinic visit (P < 0.001). The odds of having a live birth decreased by 23% and 25% with each additional NVPL and VPL, respectively. This study may be limited by its retrospective design. Some of our data, including home pregnancy tests and obstetric history, are based on patient self-reporting, which could have overstated the true prevalence of NVPLs. Another limitation is the lack of available live birth data for all patients at the time of the analysis. To our knowledge, this is the first study to examine and analyze the reproductive outcomes of patients with pure NVPLs in a substantial cohort of patients with RPL. NVPLs seem to affect future live births the same way as clinical miscarriages, which supports their inclusion in RPL definitions. This study was supported in part by Canadian Institute Heath Grant (CIHR): Reference Number/W11-179912 and Women's Health Research Institute (WHRI), Vancouver, BC, Canada. M.A.B: Research grants from Canadian Institute for Health Research (CIHR) and Ferring Pharmaceutical. M.A.B. is on the advisory board for AbbVie and Baxter. N/A.

Consequences of early thyroid ultrasound on subsequent tests, morbidity and costs: an explorative analysis of routine health data from German ambulatory care

ObjectivesThis study aims to evaluate whether the use of thyroid ultrasound (US) early in the work-up of suspected thyroid disorders triggers cascade effects of medical procedures and to analyse effects...