scholarly journals Levothyroxine prescribing and laboratory test use after a minor change in reference range for thyroid-stimulating hormone

2020 ◽  
Vol 192 (18) ◽  
pp. E469-E475
Author(s):  
Christopher Symonds ◽  
Gregory Kline ◽  
Inelda Gjata ◽  
Marianne Sarah Rose ◽  
Maggie Guo ◽  
...  
Author(s):  
Ville L. Langén ◽  
Teemu J. Niiranen ◽  
Juhani Mäki ◽  
Jouko Sundvall ◽  
Antti M. Jula

AbstractPrevious studies with mainly selected populations have proposed contradicting reference ranges for thyroid-stimulating hormone (TSH) and have disagreed on how screening, age and gender affect them. This study aimed to determine a TSH reference range on the Abbott Architect ci8200 integrated system in a large, nationwide, stratified random sample. To our knowledge this is the only study apart from the NHANES III that has addressed this issue in a similar nationwide setting. The effects of age, gender, thyroid peroxidase antibody (TPOAb)-positivity and medications on TSH reference range were also assessed.TSH was measured from 6247 participants randomly drawn from the population register to represent the Finnish adult population. TSH reference ranges were established of a thyroid-healthy population and its subpopulations with increasing and cumulative rigour of screening: screening for overt thyroid disease (thyroid-healthy population, n=5709); screening for TPOAb-positivity (risk factor-free subpopulation, n=4586); and screening for use of any medications (reference subpopulation, n=1849).The TSH reference ranges of the thyroid-healthy population, and the risk factor-free and reference subpopulations were 0.4–4.4, 0.4–3.7 and 0.4–3.4 mU/L (2.5th–97.5th percentiles), respectively. Although the differences in TSH between subgroups for age (p=0.002) and gender (p=0.005) reached statistical significance, the TSH distribution curves of the subgroups were practically superimposed.We propose 0.4–3.4 mU/L as a TSH reference range for adults for this platform, which is lower than those presently used in most laboratories. Our findings suggest that intensive screening for thyroid risk factors, especially for TPOAb-positivity, decreases the TSH upper reference limit.


2018 ◽  
Vol 31 (12) ◽  
pp. 766
Author(s):  
Sofia Macedo Silva ◽  
Alexandra Carvalho ◽  
Maria Lopes- Pereira ◽  
Vera Fernandes

Introduction: Subclinical hypothyroidism, defined as an increase of thyroid stimulating hormone levels with normal levels of thyroid hormones, could have a multiorgan impact. There seem to be differences in the elderly (over 65 years of age) which indicate that there should be a different approach in terms of diagnosis and the treatment.Material and Methods: Electronic database search and narrative bibliographical review.Results: Different case studies showing the multiorgan consequences of subclinical hypothyroidism suggest that, in the elderly, there is a minor impact or even a lack of repercussion, especially in those over 80 - 85 years old. Additionally, there is evidence indicating that the levels of thyroid stimulating hormone rise with the age of the patient. The standard treatment, in the beginning, is a low dose of levothyroxine when the levels of thyroid stimulating hormone are over 10.0 mIU/L, when there are noticeable symptoms or positive anti-thyroid antibodies. However, the treatment is not consensual when the levels of thyroid stimulating hormone are between 4.5 and 10.0 mIU/L, in such a way that the TRUST study concluded that no benefits have outcome from treating these patients. Discussion: The non-definition of the reference range and the age gap are the key factors that contribute the most to biased results. However, there is consensus regarding non-treatment of mild thyroid dysfunctions (4.5 - 7.0 mIU/L) in the elderly, particularly above 80 years of age. Nevertheless, for positive anti-thyroid antibodies, suggestive ultrasound changes or iatrogenic side effects, the reference level should be 4.5 mIU/L. Conclusion: The general impact of subclinical hypothyroidism is different in elderly people, meaning that an individualized therapeutic approach and long-term monitoring is the appropriate strategy.


2011 ◽  
Vol 9 (1) ◽  
pp. 51-57 ◽  
Author(s):  
Anna Boggio ◽  
Fulvio Muzio ◽  
Michela Fiscella ◽  
Domenico Sommariva ◽  
Adriana Branchi

Author(s):  
S Chatterjee ◽  
BP O'Malley ◽  
DE Price ◽  
AM Fielding ◽  
R Aitken

Background: In laboratories employing 'front-line' sensitive thyroid-stimulating hormone (TSH) measurement, it is generally accepted that a fully suppressed serum TSH concentration (third-generation assay) alongside normal serum concentrations of free thyroid hormones indicates subclinical hyperthyroidism. However, other explanations are often provided for low but detectable serum TSH concentrations, such as drug effects or non-thyroidal illness. Methods: We investigated 25 consecutive ambulant individuals, identified over an 18-month period as having low but not fully suppressed TSH concentrations (third-generation assay; sensitivity 0.003 mIU/L) with additional free thyroxine (T4), free tri-iodothyronine (T3) and thyroid microsomal antibody estimations and thyroid isotope scanning (technetium). Results: Concentrations of serum hormones (median, inter-quartile range) were: TSH, 0.23, 0.17-0.26 mIU/L (reference range 0.34-5.6 mIU/L); free T4, 14.6, 10.6- 17.6 pmol/L (reference range 10-25 pmol/L); free T3, 6.1, 5.7-6.6 pmol/L (reference range 4.5-7.5 pmol/L). Thyroid antibodies were negative in all but one individual. On isotope scanning, nine individuals had hot nodules and ten individuals had multinodular goitres (MNG). Of the six with normal scans, ultrasound scanning showed a definite MNG ( n = 1) and early MNG ( n = 2). Conclusions: A low but detectable serum TSH concentration, obtained using a third-generation assay, found in an ambulant individual, is frequently a pointer to underlying thyroid disease.


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