Background: The serum concentration of thyrotropin (TSH) represents a first-line test in diagnostic algorithms. The estimation of TSH Reference Intervals (RIs) is still a matter of debate due to the high prevalence of subclinical disease making difficult the definition of truly healthy subjects. The aim of this study was to estimate TSH RIs in healthy subjects and to evaluate the effect of age and gender on TSH concentration. Methods: 44156 TSH data were collected between July 2012 and April 2018 at the C.O.U. of Laboratory Medicine, University-Hospital, Palermo. Common and sex-specific reference intervals were estimated by Arzideh’s indirect method after exclusion of individuals younger than 15 years, subjects with repeated TSH test and with abnormal free thyroxine, free triiodothyronine or anti-thyroid-peroxidase antibodies. The combined effect of age and gender on TSH values was evaluated. Results: Reference intervals estimated in the selected individuals (n=22602) were respectively 0.18-3.54 mIU/L (general), 0.19-3.23 mIU/L (men) and 0.18-3.94 mIU/L (women). Women showed significantly higher median TSH than men (1.46 vs 1.39 mIU/L; p<0.0001). Both in men and in women, median TSH decreased along age; however, although up to 60 years men and women showed similar values, afterwards women showed constantly higher TSH than men. Accordingly, statistical analysis showed a significant interaction between gender and age (p=0.001), suggesting that the effect of age on TSH is different between genders. Conclusions: Our findings suggest that the indirect method, with appropriate cleaning of data, could be useful to define TSH RIs.

Reference interval by indirect approach of serum thyrotropin (TSH) in a Mediterranean adult population and association with age and gender

Lo Sasso B;
2019-01-01

Abstract

Background: The serum concentration of thyrotropin (TSH) represents a first-line test in diagnostic algorithms. The estimation of TSH Reference Intervals (RIs) is still a matter of debate due to the high prevalence of subclinical disease making difficult the definition of truly healthy subjects. The aim of this study was to estimate TSH RIs in healthy subjects and to evaluate the effect of age and gender on TSH concentration. Methods: 44156 TSH data were collected between July 2012 and April 2018 at the C.O.U. of Laboratory Medicine, University-Hospital, Palermo. Common and sex-specific reference intervals were estimated by Arzideh’s indirect method after exclusion of individuals younger than 15 years, subjects with repeated TSH test and with abnormal free thyroxine, free triiodothyronine or anti-thyroid-peroxidase antibodies. The combined effect of age and gender on TSH values was evaluated. Results: Reference intervals estimated in the selected individuals (n=22602) were respectively 0.18-3.54 mIU/L (general), 0.19-3.23 mIU/L (men) and 0.18-3.94 mIU/L (women). Women showed significantly higher median TSH than men (1.46 vs 1.39 mIU/L; p<0.0001). Both in men and in women, median TSH decreased along age; however, although up to 60 years men and women showed similar values, afterwards women showed constantly higher TSH than men. Accordingly, statistical analysis showed a significant interaction between gender and age (p=0.001), suggesting that the effect of age on TSH is different between genders. Conclusions: Our findings suggest that the indirect method, with appropriate cleaning of data, could be useful to define TSH RIs.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11387/193471
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