Should We Really Determine a Reference Population for the Definition of Thyroid-Stimulating Hormone Reference Interval?

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.

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A raised thyroid stimulating hormone result - a 12-month follow-up study in general practice

Journal of Primary Health Care ◽

10.1071/hc10029 ◽

2010 ◽

Vol 2 (1) ◽

pp. 29 ◽

Cited By ~ 1

Author(s):

Veronique Gibbons ◽

John Conaglen ◽

Ross Lawrenson

Keyword(s):

General Practice ◽

Quantitative Research ◽

Best Practice ◽

Adult Population ◽

Laboratory Data ◽

Reference Interval ◽

Thyroid Stimulating Hormone ◽

Thyroid Function Tests ◽

Stimulating Hormone

INTRODUCTION: Subclinical hypothyroidism (SCH) is common in older patients. AIM: To review the management of patients identified with a raised thyroid stimulating hormone (TSH) result in a 12-month period and compare this to current guidelines from the New Zealand Best Practice Advocacy Centre (BPAC). METHODS: We collected laboratory data on thyroid function tests (TFTs) that were reported between December 2005 and November 2006 from two general practices with an adult population of approximately 21 000. Data were collected on symptoms, investigations, thyroid medication, family history and comorbidities. We used chi-squared tests to compare findings by age, gender and ethnicity. RESULTS: Older women of European descent were more likely to be to have initial results suggesting SCH. The number of follow-up tests ranged from 0 to 5 tests in a 12-month period. Forty-eight percent of individuals did not have any follow-up investigations. Seventy-three percent of FT4 tests taken are requested concurrently with TSH. Of those who had a repeat TSH test, just over 40% had a result within the reference interval. Twenty-eight percent had two TSH results consistent with SCH. Thirty-five percent of patients with antibody results were positive. The most commonly-recorded symptoms were tiredness and weight gain. DISCUSSION: We found inconsistencies in the management of SCH which were not related to patient characteristics such as age, gender or ethnicity. Further research is needed to determine if SCH is associated with increased morbidity and to provide a clear rationale for management of patients with SCH. KEYWORDS: Hypothyroidism; family practice; quantitative research; general practice

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Harmonization of Serum Thyroid-Stimulating Hormone Measurements Paves the Way for the Adoption of a More Uniform Reference Interval

Clinical Chemistry ◽

10.1373/clinchem.2016.269456 ◽

2017 ◽

Vol 63 (7) ◽

pp. 1248-1260 ◽

Cited By ~ 28

Author(s):

Linda M Thienpont ◽

Katleen Van Uytfanghe ◽

Linde A C De Grande ◽

Dries Reynders ◽

Barnali Das ◽

...

Keyword(s):

Total Error ◽

Method Comparison ◽

Reference Interval ◽

Thyroid Stimulating Hormone ◽

Thyroid Function Tests ◽

Nonparametric Bootstrap ◽

Serum Samples ◽

Global Harmonization ◽

Method Comparison Study ◽

Stimulating Hormone

Abstract BACKGROUND The IFCC Committee for Standardization of Thyroid Function Tests developed a global harmonization approach for thyroid-stimulating hormone measurements. It is based on a multiassay method comparison study with clinical serum samples and target setting with a robust factor analysis method. Here we describe the Phase IV method comparison and reference interval (RI) studies conducted with the objective to recalibrate the participating assays and demonstrate the proof-of-concept. METHODS Fourteen manufacturers measured the harmonization and RI panel; 4 of them quantified the harmonization and first follow-up panel in parallel. All recalibrated their assays to the statistically inferred targets. For validation, we used desirable specifications from the biological variation for the bias and total error (TE). The RI measurements were done with the assays' current calibrators, but data were also reported after transformation to the new calibration status. We estimated the pre- and postrecalibration RIs with a nonparametric bootstrap procedure. RESULTS After recalibration, 14 of 15 assays met the bias specification with 95% confidence; 8 assays complied with the TE specification. The CV of the assay means for the harmonization panel was reduced from 9.5% to 4.2%. The RI study showed improved uniformity after recalibration: the ranges (i.e., maximum differences) exhibited by the assay-specific 2.5th, 50th, and 97.5th percentile estimates were reduced from 0.27, 0.89, and 2.13 mIU/L to 0.12, 0.29, and 0.77 mIU/L. CONCLUSIONS We showed that harmonization increased the agreement of results from the participating immunoassays, and may allow them to adopt a more uniform RI in the future.

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Comparison of method-related reference intervals for thyroid hormones: studies from a prospective reference population and a literature review

Annals of Clinical Biochemistry International Journal of Laboratory Medicine ◽

10.1177/0004563217691549 ◽

2017 ◽

Vol 55 (1) ◽

pp. 107-112 ◽

Cited By ~ 6

Author(s):

Julian H Barth ◽

Ahai Luvai ◽

Nuthar Jassam ◽

Wycliffe Mbagaya ◽

Eric S Kilpatrick ◽

...

Keyword(s):

Thyroid Hormone ◽

Literature Review ◽

Thyroid Hormones ◽

Reference Population ◽

Reference Intervals ◽

Thyroid Stimulating Hormone ◽

Analytical Platforms ◽

Abbott Architect ◽

Roche Cobas ◽

Stimulating Hormone

Introduction Reference intervals are dependent on the reference population, the analytical methods and the way the data are handled statistically. Individual method-related differences have been studied but the comparative differences in reference intervals have not. Methods We studied a reference population of healthy adult subjects and measured free thyroxine and thyroid-stimulating hormone by the four most commonly used analytical platforms used in the UK. Subjects were excluded if they were > 65 years or had positive thyroid peroxidase antibodies. We also performed a systematic literature review of thyroid hormone reference interval studies in non-pregnant adults. Results In total, 303 subjects were recruited and 42 excluded. The central 95th centile values for thyroid-stimulating hormone (mIU/L) were Abbott Architect (0.51–3.67); Beckman Unicel DxI (0.57–3.60); Roche Cobas (0.60–4.31) and Siemens Advia Centaur XP (0.63–4.29). The 95th centile values for thyroxine (pmol/L) were Abbott Architect (10.6–15.5); Beckman Unicel DxI (7.9–13.0); Roche Cobas (12.5–19.6) and Siemens Advia Centaur XP (11.8–19.0). We identified 55 papers describing thyroid reference intervals in male and non-pregnant female adults. The values for upper and lower reference intervals by manufacturer varied but were not significantly different for thyroid-stimulating hormone but were for thyroxine. Discussion Our study demonstrates clearly that there are marked variations in the reference intervals for thyroid hormones between analytical platforms. There is an urgent need for standardization of thyroid hormone assays to permit transferability of results. Until then, guidelines will need to reflect this method-related difference.

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Establishing reference interval for thyroid-stimulating hormone in children below two-year ages in Pakistani population

Annals of Medicine and Surgery ◽

10.1016/j.amsu.2021.102601 ◽

2021 ◽

pp. 102601

Author(s):

Siraj Muneer ◽

Imran Siddiqui ◽

Hafsa Majid ◽

Lena Jafri ◽

Khadija Nuzhat Humayun ◽

...

Keyword(s):

Reference Interval ◽

Thyroid Stimulating Hormone ◽

Pakistani Population ◽

Stimulating Hormone

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Factors Influencing the Reference Interval of Thyroid Stimulating Hormone in Healthy Adults: A Systematic Review and Meta-analysis

10.21203/rs.3.rs-119463/v1 ◽

2020 ◽

Author(s):

dongyang xing ◽

Ri Li ◽

Qi Zhou ◽

Delong Liu ◽

jiancheng xu

Keyword(s):

Sample Size ◽

Old Age ◽

Age Groups ◽

Reference Interval ◽

Thyroid Stimulating Hormone ◽

Concentration Curve ◽

Detection Methods ◽

Local Conditions ◽

Important Indicator ◽

Stimulating Hormone

Abstract Background: Thyroid stimulating hormone (TSH) is an important indicator for evaluating thyroid function. Many studies have reported that the TSH reference interval is susceptible to external factors. This paper summarizes the related studies published in recent years and comprehensively analyzes the effects of these factors on the TSH reference interval in healthy people.Methods: Articles published from January 1980 to January 2020 were searched in PubMed, EMBASE, Cochrane, Scopus, Medline English databases and CNKI, WanFang and CQVIP Chinese databases. In total, 21 studies were ultimately included. All data were analyzed using Review Manager 5.3 software and STATA 16.0 software. Microsoft Excel 2010 was used to draw the TSH concentration curve changing with age, and GraphPad 6.0 was used to draw the TSH concentration curve with sex.Results: The TSH reference interval was significantly influenced by sex and age. The overall trend of TSH concentration reveals that males are lower than females. The TSH reference interval is divided into 20~59-year-old, 60~69-year-old and over 70-year-old age groups for males and 20~39-year-old, 40~49-year-old, 50~69-year-old and over 70-year-old age groups for females. Regardless of sex, TSH concentrations all increase with age. In iodine-deficient areas, TSH reference intervals are generally lower than those in iodine-sufficient or iodine-excessive areas. The TSH reference interval in Asia and North American countries is generally higher than that in most European countries. Even the detection methods are consistent, different detection instruments can affect the TSH reference interval. Sample size and race are also important factors.Conclusion: The TSH reference interval was significantly influenced by sex and age, race, region, iodine intake, sample size, detection instruments and methods, but other factors should not be ignored. Therefore, it is necessary for each laboratory to validate an appropriate TSH reference interval based on local conditions.

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Establishment of reference interval for thyroid-stimulating hormone using electrochemiluminescence assay in a healthy adult population from Fortaleza, Brazil

Archives of Endocrinology and Metabolism ◽

10.20945/2359-3997000000264 ◽

2020 ◽

Author(s):

Maria Helane C Gurgel ◽

Clarisse M. M. Ponte ◽

Rosita Fontes ◽

Ítalo V. Rocha ◽

Lívia A. A. Batista ◽

...

Keyword(s):

Healthy Adult ◽

Adult Population ◽

Reference Interval ◽

Thyroid Stimulating Hormone ◽

Stimulating Hormone

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Establishment of trimester-specific thyroid stimulating hormone and free thyroxine reference interval in pregnant Chinese women using the Beckman Coulter UniCel™ DxI 600

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm-2014-0615 ◽

2015 ◽

Vol 53 (9) ◽

Cited By ~ 8

Author(s):

Jing Zhang ◽

Wei Li ◽

Qiao-Bin Chen ◽

Li-Yi Liu ◽

Wei Zhang ◽

...

Keyword(s):

Chinese Women ◽

Reference Interval ◽

Reference Intervals ◽

Thyroid Stimulating Hormone ◽

Free Thyroxine ◽

Specific Reference ◽

Thyroid Peroxidase ◽

Cross Sectional ◽

Reported Data ◽

Stimulating Hormone

AbstractThyroid-stimulating hormone (TSH) and free thyroxine (FT4) reference intervals are essential for screening and diagnosing thyroid dysfunction during pregnancy. The aim of this study was to establish method- and trimester-specific TSH and FT4 reference intervals in pregnant Chinese women using the Beckman Coulter UniCel™ DxI 600.A cross-sectional dataset analysis was performed. A total of 3507 participants were recruited, and 2743 were eligible for analysis to set reference intervals. TSH, FT4, and thyroid peroxidase antibody (TPOAb) levels were analyzed with the Beckman Coulter UniCel™ DxI 600 AccessThe calculated reference intervals for the first, second, and third trimesters were TSH: 0.06–3.13, 0.07–4.13 and 0.15–5.02 mIU/L, respectively, and FT4: 8.72–15.22, 7.10–13.55 and 6.16–12.03 pmol/L, respectively.Our reference intervals for TSH and FT4 are distinct from the ranges reported in the DxI 600 instruction manual and previously reported data, confirming the importance of method-specific reference intervals.

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