Diagnoses of obstetric and postpartum thyroid disease: a Danish validation study.

Different diagnoses of thyroid disease are available in the 10th International Classification of Diseases (ICD-10), but the validity of diagnoses related to obstetric and postpartum thyroid disease is unknown. This was a retrospective cohort study of all patients in the North Denmark Region with a diagnosis of postpartum thyroiditis (PPT) (ICD-10: O905) from 2016 to 2019 or obstetric thyroid disease in 2019 (ICD-10: O992B (hypothyroidism) or O992C (hyperthyroidism)) registered in the Danish National Hospital Register. Information from nationwide registers and medical records were used to assess the validity. Among patients with an O905-diagnosis (n = 40), abnormal thyroid function test results were seen in all cases. A total of eight patients (20.0%) were positive for thyrotropin receptor antibodies postpartum, however, in low titers, and PPT was verified in 39 of 40 cases (97.5%). Altogether 45 of 50 patients with an O992B-diagnosis (90.0%) correctly had hypothyroidism, whereas hyperthyroidism was found in 25 of 39 patients with an O992C-diagnosis (64.1%). This is the first study to validate ICD-10 diagnoses of obstetric and postpartum thyroid disease. A high validity was seen for PPT (O905) and obstetric hypothyroidism (O992B), whereas for obstetric hyperthyroidism (O992C), the diagnosis could not be verified in one third of the cases.

Recommendations for managing patients with hypothyroidism.

ABSTRACT: The American Thyroid Association recommends levothyroxine monotherapy for treating hypothyroidism, a condition that affects 4.6% of the US population. However, up to 15% of these patients experience residual symptoms despite normalized thyroid-stimulating hormone levels, and may benefit from an endocrinology referral. Additional high-quality studies are needed to further evaluate patient preferences, as well as to investigate long-term outcomes of combination therapy and continue exploring therapeutic options for hypothyroidism management among specific patient subgroups.

The link between underactive thyroid and leg oedema.

There is an established link between hypothyroidism and leg oedema. This article presents a case study of a female known to have an underactive thyroid gland who developed symptoms and was referred to a local Lindsay Leg Club.

Impact of subclinical hypothyroidism on outcomes after coronary artery bypass grafting: a systematic review and meta-analysis.

INTRODUCTION: Coronary artery bypass grafting (CABG) is a surgical procedure that restores blood flow to heart muscle by bypassing the blocked or narrowed coronary arteries. On the other hand, subclinical hypothyroidism (SCH) is characterized by an elevated serum concentration of thyroid stimulating hormone with normal levels of serum free thyroxine. With limited research into the impact of SCH on postoperative CABG outcomes, this systematic review and meta-analysis was performed. EVIDENCE ACQUISITION: An electronic search of PubMed, Cochrane Library, and Scopus was performed from inception to April 2023. After the inclusion of five studies, a total of 2,786 patients were pooled in this quantitative synthesis. EVIDENCE SYNTHESIS: It was observed that SCH significantly increased cardiovascular mortality (OR: 2.80; 95% CI: 1.37, 5.72; P=0.005), and all-cause mortality (OR: 2.62; 95% CI: 1.80, 3.80; P<0.00001). However, no significant differences were observed for secondary outcomes, including major adverse cardiac events, incidence of postoperative stroke, and incidence of postoperative myocardial infarction. CONCLUSIONS: To the best of our knowledge, this is the first meta-analysis conducted that evaluates the impact of SCH on outcomes after CABG. The preoperative assessment of thyroid function may be considered prior to cardiovascular procedures, particularly within CABG. However, future comprehensive studies, with individual participant-level data, are necessary in order to arrive at a valid conclusion and recommendation.

Aversion of surgical exploration in patients with complex ovarian cysts secondary to overt hypothyroidism: A series of three cases.

Long-standing, overt hypothyroidism-induced bilateral multiloculated ovarian cysts represent an infrequent occurrence. Our first case, presented with bilateral complex ovarian masses, exhibited overt hypothyroidism symptoms, including lethargy, weight gain and subfertility, prompting consideration for surgical intervention. Similarly, in the second case, a girl aged 11 years with stunting, delayed bone age and academic challenges was referred for surgical exploration due to bilateral complex ovarian masses. Both cases revealed elevated thyroid-stimulating hormone levels during preoperative workup. Commencing levothyroxine replacement therapy resulted in complete regression of ovarian cysts and substantial symptom improvement within an 8-week timeframe. The third case, a previously diagnosed patient with Hashimoto's thyroiditis, benefited from the lessons gleaned in managing the initial cases, responding well to levothyroxine therapy, thereby averting the necessity for surgery in all three instances. These cases underscore the significance of considering thyroid function in the evaluation of ovarian masses and highlight the efficacy of levothyroxine replacement therapy in resolving both hypothyroidism and associated ovarian cysts, thereby obviating the need for surgical intervention.

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.

Assessment of the likelihood of hypothyroidism in dogs diagnosed with and treated for hypothyroidism at primary care practices: 102 cases (2016-2021).

BACKGROUND: There is a possibility that an incorrect diagnosis of hypothyroidism could be made in euthyroid dogs, and the prevalence of hypothyroidism in the dog population remains unknown. OBJECTIVES: To retrospectively assess the percentage of dogs diagnosed with, and treated for, hypothyroidism at first opinion practice which are likely to be hypothyroid and require levothyroxine supplementation. ANIMALS: One hundred two client-owned dogs were included in this study. MATERIALS AND METHODS: The computerized databases of 7 first opinion practices were searched to identify dogs treated with levothyroxine supplementation. Three European College of Veterinary Internal Medicine-Companian Animals (ECVIM-CA) diplomates independently assigned 1 of 4 clinical assessments to each case as follows: confirmed or likely hypothyroid, hypothyroidism suspected but not confirmed, hypothyroidism considered unlikely, and no reason to suspect hypothyroidism. They commented as to whether or not they thought levothyroxine supplementation was appropriate. RESULTS: The clinical assessments of "confirmed or likely hypothyroid"; "Hypothyroidism suspected but not confirmed"; "Hypothyroidism considered unlikely"; and "No reason to suspect hypothyroidism" was assigned respectively by Clinician 1 to 38.2%, 5.9%, 3.9%, and 52% of cases, by Clinician 2 to 48%, 22.6%, 22.6%, 6.9% of cases, and by Clinician 3 to 55.9%, 11.8%, 13.7% and 18.6%. Clinician 1, Clinician 2, and Clinician 3 considered levothyroxine supplementation not indicated in 58.8%, 52.9%, and 45.1% of cases, respectively. CONCLUSION: These results support the concern that hypothyroidism might be overly and incorrectly diagnosed in first opinion practice, and that thyroid function testing should be performed only in those dogs with a high pretest probability of the disease.

A Role for Thyroid Testing in Slipped Capital Femoral Epiphysis? 32% Rate of Abnormal Values in Tested Patients.

BACKGROUND: Hypothyroidism is a known risk factor for slipped capital femoral epiphysis (SCFE), and prior studies of hypothyroid-associated SCFE have demonstrated an incidence of up to 6%. However, there is limited evidence and no formal practice guidelines regarding whether patients presenting with SCFE should undergo screening for endocrine disorders. This study aims to investigate the incidence of abnormal thyroid function studies in patients presenting with SCFE. METHODS: This was a retrospective review of all patients aged 0 to 18 years treated for SCFE at a single pediatric hospital from January 2015 to July 2022. On presentation, patients' BMI, thyroid-stimulating hormone (TSH), free T4, vitamin D, creatinine, BUN, and HbA1c levels were documented. Follow-up and treatment for any identified endocrinopathies were noted. In addition, the chronicity, stability, and severity of their slips were recorded. RESULTS: Ninety-eight patients with 106 hips were included in this study. TSH was obtained at the time of initial presentation in 66% (n=65/98) of patients. Median TSH was 2.99 (range: 0.02 to 919, std dev: 132.4). The normal reference range for our institution is 0.5 to 4.5 mcIU/mL. Thirty-two percent (n=21/65) of patients with a documented TSH had an abnormal value. Of those patients who had an elevated TSH, 3 were diagnosed with clinical hypothyroidism and went on to treatment with levothyroxine (n=3/19, 16%), 2 patients had been started on levothyroxine before presentation (n=2/19, 11%), and 2 patients were followed in endocrinology clinic until their TSH levels had normalized without further intervention (n=2/19, 11%). CONCLUSIONS: Screening of our SCFE population revealed a 32% incidence of thyroid abnormalities which affected treatment in 24% of those patients. This is a much higher incidence of hypothyroid-associated SCFE than previously demonstrated in the literature and has prompted us to start including thyroid screening studies as a routine part of our workup for all patients with SCFE. LEVEL OF EVIDENCE: Level III.

Association of COVID-19 Infection with Subsequent Thyroid Dysfunction: An International Population-Based Propensity Score Matched Analysis.

Background: The COVID-19 pandemic's impact on thyroid function is a growing concern. Previous studies have produced inconclusive results, and there is a lack of comprehensive research into the long-term risks of thyroid dysfunction following COVID-19 infection. Methods: In this retrospective cohort study, we used data from the TriNetX international database, which includes electronic health records from a broad, diverse patient population. We compared patients with COVID-19 (cases) to those without (controls), matching for age, sex, race, and comorbidities using propensity score matching. The primary outcome was the diagnosis of thyroid dysfunction (thyrotoxicosis or hypothyroidism) within a 12-month period, analyzed using hazard ratios (HRs) and Kaplan-Meier curves, and stratified by age and sex. Results: Initially, the study included 1,379,311 COVID-19 patients and 6,896,814 non-COVID-19 patients from the TriNetX database. After matching, the cohorts were comparable in demographics and baseline characteristics. This study consistently demonstrated a significant increase in the risk of thyroid dysfunction, including thyrotoxicosis and hypothyroidism, among COVID-19 patients compared to non-COVID-19 patients. In the short term (3 months postexposure), the COVID-19 group exhibited a HR of 2.07 (95% confidence interval [CI] 2.01-2.12) for thyroid dysfunction, which included both thyrotoxicosis (HR 2.10, CI 1.92-2.29) and hypothyroidism (HR 2.08, CI 2.01-2.13). This heightened risk persisted over the long term (up to 12 months), with HRs indicating an ∼2.01-fold increased risk for overall thyroid dysfunction, a 1.8-fold increased risk for thyrotoxicosis, and a 2.04-fold increased risk for hypothyroidism. Subgroup analysis, stratified by age and sex, revealed a notably higher risk of thyroid dysfunction in patients aged 65 and above (HR 2.18, CI 2.11-2.25), compared to those in the under-65 age group (HR 1.97, CI 1.91-2.03). Both male and female patients were associated with an elevated risk, with females showing a slightly higher association with thyroid dysfunction (HR 2.12, CI 2.06-2.16) compared to males (HR 1.76, CI 1.69-1.82). Conclusions: COVID-19 infection was associated with an increased risk of thyroid dysfunction, including thyrotoxicosis and hypothyroidism, regardless of age or sex, during a 12-month follow-up period. Further research is required to validate these findings.

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

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

Hypothyroidism among children and adolescents with nephrotic syndrome in Mulago National Referral Hospital, Kampala, Uganda; a cross-sectional study.

BACKGROUND: Nephrotic syndrome (NS) is the commonest glomerular disease among children. It is characterized by heavy proteinuria and is a risk factor for hypothyroidism in the affected children. Hypothyroidism is of concern because it affects the physical and intellectual development of children and adolescents. This study sought to establish the prevalence and factors associated with hypothyroidism among children and adolescents with NS. METHODS: A cross-sectional design was used to study 70 children and adolescents aged 1-19 years diagnosed with nephrotic syndrome and being followed up in the kidney clinic in Mulago National Referral Hospital. Questionnaires were used to collect patients' socio-demographics and clinical information. A blood sample was taken for analysis for thyroid stimulating hormone (TSH) and free thyroxine (FT4), renal function tests and serum albumin. Hypothyroidism included both overt and subclinical forms. Overt hypothyroidism was defined as TSH level > 10 mU/L and FT4 < 10pmol/L, or FT4 < 10pmol/l with normal TSH, or TSH < 0.5mU/l. Sub-clinical hypothyroidism was defined as TSH ranging between 5 and10 mU/L with normal age appropriate FT4 levels. Urine samples were collected and taken for a dipstick examination. The data was analyzed using STATA version 14. The Bayesian Logistic regression analysis approach was used to estimate odds ratios (OR) and their associated 95% credible intervals. All predictor variables with p value < 0.05 at frequentist statistical analysis were considered significant. RESULTS: The mean age (standard deviation) of participants was 9 years (3.8). There were more males; 36 of 70 (51.4%). The prevalence of hypothyroidism was 23% (16/70 participants). Of the 16 children with hypothyroidism, 3 (18.7%) had overt hypothyroidism while 13 had subclinical hypothyroidism. Only low serum albumin was found to be strongly associated with hypothyroidism; Bayesian OR 132.57 (CI 9.13-567.10) with a frequentist OR of 37 and a p value of 0.001. CONCLUSION: The prevalence of hypothyroidism among children and adolescent with nephrotic syndrome attending Mulago Hospital paediatric kidney clinic was 23%. Hypoalbuminemia was found to be associated with hypothyroidism. Therefore, children and adolescents that have severely low levels of serum albumin should be screened for hypothyroidism and linked to endocrinologists for care.

Differentiation and Treatment of Hypothyroidism, Functional Hypothyroidism, and Functional Metabolism.

Less than optimal thyroid effects can occur for many reasons, including lack of production, excessive binding, reduced conversion to the active form of thyroid, poor intracellular transport, poor receptor response, or autoimmune and toxicity issues. Differentiation of where the problem or problems causing the symptoms of hypothyroidism to occur is a key to the return to optimal thyroid response and successful treatment outcome. The concept of hypothyroidism, functional hypothyroidism, and functional hypometabolism as an alternative method to describe classical subclinical hypothyroidism symptoms according to the source of the malfunction are discussed in this article. The author also presents a unique method of using standard thyroid measurements to determine the areas of dysfunction and discusses the possible reasons for low production, excessive binding, poor conversion, and suboptimal receptor response. Appropriate treatment options for each area are discussed, including nutritional requirements. Thyroid replacement therapy options are presented and individualization of therapy based on need established with use of the thyroid gradient levels is discussed. Individualization of thyroid therapy will often require the use of compounded T3 or T4/T3 combination therapy. Compounding thyroid replacement allows for avoiding fillers that can interfere with absorption, unwanted diluents, unknown or nonstandardized ingredients from animal sources, providing more sustained action with less side effects, and individualizing the ratio of T4 and T3 initially, and as improvements are made in the patient's ability to convert T4 to T3.

Hypothyroidism in acute coronary syndrome - A prospective Indian study.

BACKGROUND: Evidence suggests that hypothyroidism may be associated with an increased risk of acute coronary syndrome (ACS). The data regarding the influence of hypothyroidism on cardiovascular disease in the Asian population is conflicting. Therefore, we undertook this study to assess the overall prevalence of hypothyroidism in Acute Coronary Syndrome (ACS) patients and determine if there is a relationship between hypothyroidism, both sub-clinical and overt and other significant risk factors of ACS in an Indian population. METHODS: We studied 487 hospitalized patients between March 2018 and February 2021 with a diagnosis of ACS to determine the prevalence of hypothyroidism, both clinical and sub-clinical and their relationship with other known coronary risk factors. Thyroid function Tests - free T3, free T4 and TSH were collected from all the patients within 24 h of their admission to the coronary care unit (CCU) of 2 major hospitals in New Delhi and Imphal (Manipur). RESULTS: Subclinical hypothyroidism was prevalent in 44 (9 %), followed by overt hypothyroidism in 25 (5.2 %). Subclinical hypothyroidism was more common in females, whereas overt hypothyroidism was more common in males. ST Elevation Myocardial Infarction (STEMI) (52 %), followed by Non-ST-Elevation Myocardial Infarction (NSTEMI) (25 %), was the commonest diagnosis at presentation. Patients with overt hypothyroidism showed a higher proportion of increased triglyceride levels. Patients with hypothyroidism had no differences in the prevalence of concomitant diabetes hypertension and other coronary risk factors. CONCLUSIONS: Patients with ACS without known thyroid disorders should be screened for hypothyroidism since it is found frequently. There might be a case to treat their thyroid dysfunction appropriately.

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.

Subclinical hypothyroidism in the infertile female population: a guideline.

There is controversy regarding whether to treat subtle abnormalities of thyroid function in infertile female patients. This guideline document reviews the risks and benefits of treating subclinical hypothyroidism in female patients with a history of infertility and miscarriage, as well as obstetric and neonatal outcomes in this population.

Prevalence and risk factors for subclinical hypothyroidism in older patients with major depressive disorder.

BACKGROUND: Subclinical hypothyroidism (SCH) is highly correlated with major depressive disorder (MDD). However, the prevalence and risk factors for SCH in older patients with MDD have rarely been reported in China. METHODS: This cross-sectional study included 266 older MDD patients with SCH was performed. Clinical and anthropometric, biochemical, and thyroid function data were collected. Depression, anxiety, and psychotic symptoms were assessed using the Hamilton Depression Scale, the Hamilton Anxiety Scale, and the Positive and Negative Syndrome Scale positive subscale, respectively. RESULTS: Among older patients with MDD, the prevalence of SCH was 64.7% (172/266). Compared to patients without SCH, older MDD patients with SCH had a longer disease course and higher TSH, A-TG, A-TPO, HDL-C, LDL-C, TC, FPG, and systolic pressure levels (all P ≤ 0.002). Furthermore, disease progression (OR 1.082, 95% CI 1.020-1.147, P = 0.009), A-TG (OR 1.005, 95% CI 1.001-1.009, P = 0.017), TC (OR 2.024, 95% CI 1.213-3.377, P = 0.007), FPG (OR 2.916, 95% CI 1.637-5.194, P < 0.001), systolic pressure (OR 1.053, 95% CI 1.008-1.100, P = 0.022) were independently associated with SCH, in older patients with MDD. CONCLUSIONS: Our findings suggest a high prevalence of SCH in older patients with MDD. Several demographic and clinical variables were independently associated with SCH in older patients with MDD.

Assessment of Primary Hemostasis by Platelet Function Analyzer-100 and its Relation with TSH and FT4 Levels in Newly Diagnosed Overt and Subclinical Hypothyroid Patients.

Various abnormalities of coagulation such as primary hemostasis, secondary hemostasis and fibrinolysis have been reported in patients with subclinical and overt hypothyroidism. Platelets are major elements of primary hemostasis and endothelial repair. Platelet size, shape and number are the determinant of platelet function. The objective of this study was to assess primary hemostasis by PFA-100 (Platelet Function Analyzer-100) and its relation with TSH and FT4 levels in newly diagnosed overt and subclinical hypothyroid patients. This cross-sectional study was conducted in the Department of Physiology, Dhaka Medical College, Bangladesh from January 2016 to December 2016. Twenty overt and 20 subclinical hypothyroid patients with age ranging from 18 to 55 years were selected as study group and twenty age and sex matched healthy subjects were considered as control group. Patients were selected from Outpatients Department of Endocrinology and Nuclear Medicine & Allied Sciences of Dhaka Medical College Hospital, Dhaka on the basis of exclusion and inclusion criteria. For assessment of primary hemostasis, PFA-100 was analyzed by SIEMENS-INNOVANCE-PFA-200. For statistical analysis Unpaired Student's 't' test, Chi square test and Pearson's correlation co-efficient (r) test were performed. PFA-100 was significantly higher (p<0.001) in overt and subclinical hypothyroid patients as compared to healthy adult subjects. In overt and subclinical hypothyroidism using PFA-100, we found that the existence of a hypocoagulable state is due to a defect in primary hemostasis. Moreover, PFA-100 may replace the in-vivo bleeding time as a screening test for primary hemostasis in routine clinical practice.