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Background: Thyroid diseases are highly prevalent worldwide, but their diagnosis remains a challenge. We established reference intervals (RIs) for thyroid-associated hormones and evaluated the prevalence of thyroid diseases in China., Methods: After excluding outliers based on the results of ultrasound screening, thyroid antibody tests, and the Tukey method, the medical records of 20,303 euthyroid adults, who visited the Department of Health Care at Peking Union Medical College Hospital from January 2014 to December 2018, were analyzed. Thyroid-associated hormones were measured by the Siemens Advia Centaur XP analyzer. The RIs for thyroid-associated hormones were calculated according to the CLSI C28-A3 guidelines, and were compared with the RIs provided by Siemens. The prevalence of thyroid diseases over the five years was evaluated and compared using the chi-square test., Results: The RIs for thyroid stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), total thyroxine (TT4), and total triiodothyronine (TT3) were 0.71-4.92 mIU/L, 12.2-20.1 pmol/L, 3.9-6.0 pmol/L, 65.6-135.1 nmol/L, and 1.2-2.2 nmol/L, respectively. The RIs of all hormones except TT4 differed significantly between males and females. The RIs of TSH increased with increasing age. The prevalence of overt hypothyroidism, overt hyperthyroidism, subclinical hypothyroidism, and subclinical hyperthyroidism was 0.5% and 0.8%, 0.2% and 0.6%, 3.8% and 6.1%, and 3.3% and 4.7% in males and females, respectively, which differed from those provided by Siemens., Conclusions: Sex-specific RIs were established for thyroid-associated hormones, and the prevalence of thyroid diseases was determined in the Chinese population.

Background: While many studies have established reference intervals (RIs) for thyroid hormones using patient data, this approach has not been validated. Therefore, in this study, we aimed to validate an approach for establishing RIs for thyroid hormones only using patient data from clinical laboratories., Methods: We established two derived databases: derived database* and derived database#. Reference individuals in derived database* were selected using strict exclusion criteria, and the RIs established by the database were considered standard RIs (RIs*). Individuals in derived database# were the physical examination population, whose information was downloaded directly from the Laboratory Information System, and RIs established from this database were evaluated (RIs#). The comparative confidence interval (CI) method and consistency of the decision results based on external databases were used to compare RIs* and RIs#., Results: RIs# and RIs* for the thyroid hormones tested were similar. The 90% CIs of the upper and lower limits of RIs for most thyroid hormones overlapped between RIs# and RIs*, and the limit of RIs# was within the 90% CI of RIs*. The consistency rates for the results of the RIs* and RIs# in the external database were greater than 98% for all thyroid hormones tested., Conclusion: It was possible to establish RIs for thyroid hormones using only patient data from clinical laboratories after adopting appropriate statistical methods., (Copyright © 2020 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.)

Objective: This nationwide study aimed to establish Chinese specific reference intervals (RIs) for thyroid related tests: thyroid stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), total thyroxine (TT4), total triiodothyronine (TT3), anti-thyroid peroxidase (TPO-Ab) and anti-thyroglobulin antibodies (TG-Ab)., Method: Apparently healthy individuals (n = 2380) were recruited from Beijing, Guizhou, Urumqi, Dongying, Shenzhen, and Qiqihar in China. All the tests were measured by immunoassay testing. Ultrasonography was performed to exclude thyroid nodules. Multiple regression analysis was performed to identify sources of variation (SVs). Standard deviation ratio (SDR) was calculated by ANOVA for judging the need to partition RI by any given SV. RIs were computed by the parametric method., Results: TPO-Ab and TG-Ab cutoffs were determined as 5 mIU/L and 2 IU/L, respectively using probability plot analysis and extrapolation of the central linear segment. Individuals with thyroid nodule and/or autoantibodies showed altered levels of thyroid hormones, and were thus excluded (n reduced to 1828). Gender difference was observed for FT3 and TT3 with females having lower levels than males. A significant relationship between age and FT3 was observed in males by Spearman correlation analysis (r = -0.231, p < .05). Although the SDR for gender difference in TSH levels was low, the difference in the upper limits of the RI was beyond allowable bias, and thus RIs (mIU/L) were partitioned by sex: females 0.72-5.50, males 0.70-4.59., Conclusion: By this nationwide study, RIs for thyroid hormones and cutoff values for anti-thyroid autoantibodies were established as matched to the Chinese population., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Thyroid hormone reference intervals are crucial for diagnosing and monitoring thyroid dysfunction during early pregnancy, and the dynamic change trend of thyroid hormones during pregnancy can assist clinicians to assess the thyroid function of pregnant women. This study aims to establish early pregnancy related thyroid hormones models and reference intervals for pregnant women. We established two derived databases: derived database* and derived database#. Reference individuals in database* were used to establish gestational age-specific reference intervals for thyroid hormones and early pregnancy related thyroid hormones models for pregnant women. Individuals in database# were apparently healthy non-pregnant women. The thyroid hormones levels of individuals in database# were compared with that of individuals in database* using nonparametric methods and the comparative confidence interval method. The differences in thyroid stimulating hormone and free thyroxine between early pregnant and non-pregnant women were statistically significant (p<0.0001). The reference intervals of thyroid stimulating hormone, free thyroxine and free triiodothyronine for early pregnant women were 0.052–3.393 μIU/ml, 1.01–1.54 ng/dl, and 2.51–3.66 pg/ml, respectively. Results concerning thyroid stimulating hormone and free thyroxine reference intervals of early pregnancy are comparable with those from other studies using the same detection platform. Early pregnancy related thyroid hormones models showed various change patterns with gestational age for thyroid hormones. Early pregnancy related thyroid hormones models and reference intervals for pregnant women were established, so as to provide accurate and reliable reference basis for the diagnosing and monitoring of maternal thyroid disfunction in early pregnancy. [ABSTRACT FROM AUTHOR]