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Frequency, determinants and costs of thyroid function testing in a laboratory serving a large population

Lookup NU author(s): Professor David Kennedy, Dr Salman Razvi



This is the authors' accepted manuscript of an article that has been published in its final definitive form by BioScientifica Ltd, 2022.

For re-use rights please refer to the publisher's terms and conditions.


Objective: To assess the rationale and frequency of thyroid function testing and to analyse factors that influence serum thyrotropin (TSH) levels.Patients, Design and Main Outcome Measures: Serum TSH levels were evaluated in a hospital laboratory serving a population of 604,000 in 2018. Patients on medications or with conditions affecting thyroid function were excluded. Frequency of thyroid function testing by age and sex was assessed and relationship between serum TSH with potential predictor variables was analysed using ordinary least square regression analysis allowing for potential nonlinearity. Results: Twenty eight percent of the local population had their thyroid function tested at least once in 2018 with significant differences by sex (28.2% women vs 23.4% men) and by age groups, with less than 2% of <16-year-old and more than 50% of >80-year-old people being tested. Most of the symptoms commonly attributed to thyroid dysfunction were not higher in the thyroid dysfunction groups. Serum TSH levels were higher in older people particularly after the age of 60 years, in women (by 0.1 mIU/L), during the early hours of the morning, and in winter and spring seasons. There was remarkable uniformity in the frequency of subclinical thyroid dysfunction, as well as substantial cost savings, if TSH reference intervals were recalculated across sexes, age groups, time-periods and seasons. Conclusions: Serum TSH is frequently tested in the population but is not a good discriminant of symptoms attributed to thyroid dysfunction. Furthermore, considering the influence of factors on TSH reference limits could significantly impact patient care and resource utilisation.

Publication metadata

Author(s): Javaid U, Kennedy D, Addison C, Tsatlidis V, Razvi S

Publication type: Article

Publication status: Published

Journal: European Journal of Endocrinology

Year: 2022

Volume: 186

Issue: 5

Pages: 553-560

Print publication date: 01/05/2022

Online publication date: 29/03/2022

Acceptance date: 11/03/2022

Date deposited: 11/03/2022

ISSN (print): 0804-4643

ISSN (electronic): 1479-683X

Publisher: BioScientifica Ltd


DOI: 10.1530/EJE-21-1172

ePrints DOI: 10.57711/kjde-m573


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