THYROID FUNCTION TESTS: A REVIEW

2021 ◽  
pp. 73-76
Author(s):  
Vasudev Sankhla ◽  
Aman Deep

Thyroid function tests are one of the most common endocrine panels in general practice because a good understanding of when to order them, indications for treatment are important for the optimal treatment of thyroid dysfunction. Thyroid-stimulating hormone (TSH) should be the rst test to be performed on any patient with suspected thyroid dysfunction and in follow-up of individuals on treatment. It is useful as a rst-line test because even small changes in thyroid function are sufcient to cause a signicant increase in TSH secretion. Thyroxine levels may be assessed in a patient with hyperthyroidism, to determine the severity of hyperthyroxinemia. Antithyroid peroxidase measurements should be considered while evaluating patients with subclinical hypothyroidism and can facilitate the identication of autoimmune thyroiditis during the evaluation of nodular thyroid disease. The measurement of TSH receptor antibody must be considered when conrmation of Graves’ disease is needed and radioactive iodine uptake cannot be done.

2021 ◽  
Vol 184 (5) ◽  
pp. 699-709
Author(s):  
Irene Campi ◽  
Ilaria Bulgarelli ◽  
Antonella Dubini ◽  
Giovanni Battista Perego ◽  
Elena Tortorici ◽  
...  

Objective Alterations in thyroid function tests (TFTs) have been recorded during SARS-CoV-2 infection as associated to either a destructive thyroiditis or a non-thyroidal illness. Methods We studied 144 consecutive COVID-19 patients admitted to a single center in intensive or subintensive care units. Those with previous thyroid dysfunctions or taking interfering drugs were excluded. Differently from previous reports, TSH, FT3, FT4, thyroglobulin (Tg), anti-Tg autoantibodies (TgAb) were measured at baseline and every 3–7 days. C-reacting protein (CRP), cortisol and IL-6 were also assayed. Results The majority of patients had a normal TSH at admission, usually with normal FT4 and FT3. Low TSH levels were found either at admission or during hospitalization in 39% of patients, associated with low FT3 in half of the cases. FT4 and Tg levels were normal, and TgAb-negative. TSH and FT3 were invariably restored at the time of discharge in survivors, whereas were permanently low in most deceased cases, but only FT3 levels were predictors of mortality. Cortisol, CRP and IL-6 levels were higher in patients with low TSH and FT3 levels. Conclusions Almost half of our COVID-19 patients without interfering drugs had normal TFTs both at admission and during follow-up. In this series, the transient finding of low TSH with normal FT4 and low FT3 levels, inversely correlated with CRP, cortisol and IL-6 and associated with normal Tg levels, is likely due to the cytokine storm induced by SARS-Cov-2 with a direct or mediated impact on TSH secretion and deiodinase activity, and likely not to a destructive thyroiditis.


2017 ◽  
Vol 177 (1) ◽  
pp. 9-14 ◽  
Author(s):  
Stan Benjamens ◽  
Robin P F Dullaart ◽  
Wim J Sluiter ◽  
Michiel Rienstra ◽  
Isabelle C van Gelder ◽  
...  

Objective Amiodarone is used for the maintenance of sinus rhythm in patients with arrhythmias, but thyroid dysfunction (amiodarone-induced thyrotoxicosis (AIT) or amiodarone-induced hypothyroidism (AIH)) is a common adverse effect. As the onset of AIT and AIH may be unpredictable, the value of long-term regular monitoring of amiodarone treated patients for thyroid dysfunction is still uncertain. Design We retrospectively documented the frequency at which overt thyroid dysfunction was preceded by subclinical thyroid dysfunction. Methods We included 303 patients treated with amiodarone between 1984 and 2007. AIT was defined as a lowered TSH level with an elevated free thyroxine (FT4) and AIH was defined as an elevated TSH level with a decreased or subnormal FT4. Subclinical AIT was defined as a lowered TSH level with a normal FT4 and subclinical AIH as an elevated TSH level with a normal FT4. Results 200 men and 103 women, aged 62 ± 12.0 years, suffering from atrial (260) or ventricular (43) arrhythmias, were evaluated. During a median follow-up of 2.8 (1.0–25) years, 44 patients developed AIT and 33 AIH. In 42 (55%) patients who developed AIT/AIH, earlier thyroid function tests showed no subclinical AIT or subclinical AIH. In 35 (45%) patients, AIT/AIH was preceded by subclinical AIT or subclinical AIH (16/44 for AIT and 19/33 for AIH). Conclusions In a considerable proportion of patients who developed AIT/AIH, earlier thyroid function tests showed no subclinical AIT/AIH. Less than half of the patients with a subclinical event subsequently developed overt AIT/AIH. This study provides data to reconsider the yield of regular testing of thyroid function to predict overt thyroid dysfunction in amiodarone treated patients.


2018 ◽  
Vol 68 (675) ◽  
pp. e718-e726 ◽  
Author(s):  
Lesley Roberts ◽  
Deborah McCahon ◽  
Oliver Johnson ◽  
M Sayeed Haque ◽  
James Parle ◽  
...  

BackgroundThyroid function tests (TFTs) are among the most requested tests internationally. However, testing practice is inconsistent, and potentially suboptimal and overly costly. The natural history of thyroid function remains poorly understood.AimTo establish the stability of thyroid function over time, and identify predictors of development of overt thyroid dysfunction.Design and settingLongitudinal follow-up in 19 general practices in the UK.MethodA total of 2936 participants from the Birmingham Elderly Thyroid Study (BETS 1) with a baseline TFT result indicating euthyroid or subclinical state were re-tested after approximately 5 years. Change in thyroid-stimulating hormone (TSH), free thyroxine (FT4), and thyroid status between baseline and follow-up was determined. Predictors of progression to overt dysfunction were modelled.ResultsParticipants contributed 12 919 person-years; 17 cases of overt thyroid dysfunction were identified, 13 having been classified at baseline as euthyroid and four as having subclinical thyroid dysfunction. Individuals with subclinical results at baseline were 10- and 16-fold more likely to develop overt hypothyroidism and hyperthyroidism, respectively, compared with euthyroid individuals. TSH and FT4 demonstrated significant stability over time, with 61% of participants having a repeat TSH concentration within 0.5 mIU/L of their original result. Predictors of overt hypothyroidism included new treatment with amiodarone (odds ratio [OR] 92.1), a new diagnosis of atrial fibrillation (OR 7.4), or renal disease (OR 4.8).ConclusionHigh stability of thyroid function demonstrated over the 5-year interval period should discourage repeat testing, especially when a euthyroid result is in the recent clinical record. Reduced repeat TFTs in older individuals is possible without conferring risk, and could result in significant cost savings.


Author(s):  
E J Lamb ◽  
J Martin

It is claimed that inappropriate requesting of thyroid function tests (TFTs) is common in acutely ill patients. Consecutive inpatient TFTs ( n=129) were assessed in relation to clinical history and common symptoms and signs of thyroid disease. Requests were justified in 69% of cases, most commonly on the basis of atrial fibrillation and/or tachycardia. There were no clear reasons for requesting TFTs in the remaining cases, although the yield of abnormal results in these patients was similar to that in those with justified requests. Thyroid stimulating hormone (TSH) concentration was increased (median 7·5 mU/L, range 4·8-38·6 mU/L) in 22 patients, six of whom had biochemical and/or clinical evidence of hypothyroidism (previously undiagnosed) and five of whom had pre-existing hypothyroidism. Of the remaining 11 patients with increased TSH levels, three were confirmed to have compensated hypothyroidism; non-thyroidal illness (NTI) (including the effect of drugs) accounted for four cases. In four patients (one of whom died during the admission) follow-up was not possible. Of six patients with reduced TSH concentration (range < 0·05-0·35 mU/L), one was thyrotoxic on carbimazole, one was receiving thyroxine for hypothyroidism, one had NTI and three were lost to follow-up (two of whom died during their admission). Manifestations of thyroid disease are protean and often subtle, and TFTs are thus clinically justified in many unwell inpatients. Although NTI contributes to some cases of abnormal TSH levels, a significant number of TFT abnormalities are consistent with underlying thyroid abnormality requiring investigation/treatment.


2016 ◽  
Vol 9 (3) ◽  
pp. 126-129 ◽  
Author(s):  
Helen Robinson ◽  
Philip Robinson ◽  
Michael D’Emden ◽  
Kassam Mahomed

Background First-trimester care of maternal thyroid dysfunction has previously been shown to be poor. This study evaluates early management of thyroid dysfunction in pregnancy in Australia. Methods Patients reviewed by the Obstetric Medicine team for thyroid dysfunction from 1 January 2012 to 30 June 2013 were included. Data were collected on gestation at referral from the patient’s general practitioner to the antenatal clinic, information provided in the referral letter, thyroid function tests and thyroid medications. Results Eighty-five women were included in the study. At the time of general practitioner referral to antenatal services, 19% of women with preexisting thyroid disease had no thyroid function tested. Forty-three percent had an abnormal thyroid-stimulating hormone defined as being outside the laboratory-specific pregnancy reference range if available, or outside the level of 0.1–2.5 mIu/L in the first trimester, 0.2–3.0 mIu/L in the second trimester and 0.3–3.0 mIu/L in the third trimester. Only 21% of women increased their thyroxine dose prior to their first antenatal clinic review. Conclusion This study highlights that a significant proportion of women with known thyroid disease either have untested thyroid function in the first trimester or a thyroid-stimulating hormone outside of levels recommended by guidelines.


Author(s):  
Elif Çelik ◽  
Ayşe Anık

INTRODUCTION: Thyroid function tests are among the most frequently implemented laboratory tests in primary, and secondary healthcare institutions. The aim of the present study was to investigate the demographic and clinical characteristics and final diagnosis of children referred by primary and secondary healthcare institutions with the suspicion of an abnormality in thyroid function test and/or with the initial diagnosis of specific thyroid disease. METHODS: A total of two hundred eighty-nine pediatric patients, aged between 4 and 18 years admitted to the outpatient clinics of Behçet Uz Children’s Health and Diseases Hospital between January 2018 and January 2020, were included in the study. The patient data were obtained retrospectively from the hospital records. RESULTS: A total of 66% of the patients who were included in the study were female with a median age of 12 years (8.7-14.4), while 64% of them were pubertal; and 78% of the cases were referred by secondary healthcare institutions. The most common reason for referral was isolated elevation of thyroid stimulating hormone (TSH). A total of 56% of the patients were asymptomatic at the time of admission, and thyroid function test results of 75% of them were within normal limits. When evaluated according to their final diagnoses, the children were normal/healthy (64%), diagnosed with Hashimoto thyroiditis (30%), nodular thyroid disease (3%), Graves disease (2%) and isolated increase of TSH was related to obesity in 5 patients (1%). DISCUSSION AND CONCLUSION: It is essential to evaluate children with abnormal thyroid function test results with detailed history and physical examination. Besides, the thyroid function tests should be performed with reliable and sensitive methods in standardized laboratories to reach the correct diagnosis in these children.


2021 ◽  
Author(s):  
Ji Eun Park ◽  
Sook Min Hwang ◽  
Ji-Young Hwang ◽  
Jin Hee Moon ◽  
Ik Yang ◽  
...  

Abstract Purpose: To evaluate the association between thyroid echogenicity and heterogeneity seen on ultrasonography (US) and thyroid function in pediatric and adolescent populations with autoimmune diffuse thyroid diseases (AITD).Methods: From 2000 to 2020, we reviewed thyroid ultrasound (US) images and thyroid function statuses in 133 children and adolescent AITD patients. Our review of the images focused on decreased echogenicity and heterogeneity, which were classified into four grades.Results: Among patients with overt hypothyroidism or overt hyperthyroidism, 94.2% (65/69) showed a US grade of 3 or 4. In patients with subclinical hyper/hypothyroidism or euthyroidism, 45.3% (29/64) showed grades 1 or 2. There were no overt hyper/hypothyroidism patients with US grade 1. When we compared US grades according to thyroid status, more severe thyroid dysfunction was significantly associated with higher US grade (p=0.047). Thyroid stimulating hormone (TSH) level differed significantly according to US grades when we evaluated hyperthyroid (p=0.035) and hypothyroid (p=0.027) states independently. 11 patients showed both US grade and thyroid function status changes on follow-up US.Conclusions: In children and adolescent AITD patients, there was an association between decreased echogenicity and heterogeneity on US and thyroid dysfunction.


Author(s):  
Jayne A. Franklyn

Subclinical hypothyroidism is defined biochemically as the association of a raised serum thyroid-stimulating hormone (TSH) concentration with normal circulating concentrations of free thyroxine (T4) and free triiodothyronine (T3). The term subclinical hypothyroidism implies that patients should be asymptomatic, although symptoms are difficult to assess, especially in patients in whom thyroid function tests have been checked because of nonspecific complaints such as tiredness. An expert panel has recently classified individuals with subclinical hypothyroidism into two groups (1): (1) those with mildly elevated serum TSH (typically TSH in the range 4.5–10.0 mU/l) and (2) those with more marked TSH elevation (serum TSH >10.0 mU/l).


2020 ◽  
Vol 13 (3) ◽  
pp. e231337
Author(s):  
Michael S Lundin ◽  
Ahmad Alratroot ◽  
Fawzi Abu Rous ◽  
Saleh Aldasouqi

A 69-year-old woman with a remote history of Graves’ disease treated with radioactive iodine ablation, who was maintained on a stable dose of levothyroxine for 15 years, presented with abnormal and fluctuating thyroid function tests which were confusing. After extensive evaluation, no diagnosis could be made, and it became difficult to optimise the levothyroxine dose, until we became aware of the recently recognised biotin-induced lab interference. It was then noticed that her medication list included biotin 10 mg two times per day. After holding the biotin and repeating the thyroid function tests, the labs made more sense, and the patient was easily made euthyroid with appropriate dose adjustment. We also investigated our own laboratory, and identified the thyroid labs that are performed with biotin-containing assays and developed strategies to increase the awareness about this lab artefact in our clinics.


Author(s):  
Puja Banik ◽  
R. K. Praneshwari Devi ◽  
Aheibam Bidya ◽  
Akoijam Tamphasana ◽  
M. Agalya ◽  
...  

Background: Changes in thyroid function in normal pregnancy are well-documented but in complicated pregnancy like preeclampsia, very little is known. Studies have shown evidences of hypothyroidism in preeclampsia necessitating thyroid function tests to be done in preeclampsia. The study was done to analyze the fetomaternal outcome of preeclampsia with coexisting thyroid dysfunction.Methods: A cross-sectional analytical study was done over 18 months on 95 preeclamptic patients admitted at the antenatal ward and fetomaternal outcomes were analyzed according to thyroid status.Results: Out of 95 patients with preeclampsia, 42 (44.2%) had thyroid dysfunction. Among these 42 patients, 37 (38.9%) patients had subclinical hypothyroidism, 4 (4.2%) had overt hypothyroidism and 1 (1%) had hyperthyroidism. Severe preeclampsia was seen in 64.3% of the patients with thyroid dysfunction compared with 39.6% in euthyroid patients. The mean thyroid stimulating hormone (TSH) level was significantly higher and means free thyroxine (fT4) level was significantly lower in severe preeclampsia compared with non-severe preeclampsia. Complications like abruption, intrauterine fetal death (IUD), intrauterine growth restriction (IUGR), oligohydramnios, preterm deliveries, postpartum hemorrhage (PPH), low birth weight babies, birth asphyxia in babies and subsequent neonatal intensive care unit (NICU) admissions were significantly higher (p <0.05) in the preeclampsia patients with thyroid dysfunction in comparison with euthyroid ones.Conclusions: Hypothyroidism may be a modifiable risk factor for preeclampsia. Thyroid screening early in pregnancy may be helpful in predicting the occurrence of preeclampsia and timely thyroid hormone administration can reduce the maternal and perinatal morbidity and mortality associated with preeclampsia.


Sign in / Sign up

Export Citation Format

Share Document