The Thyrotropin Reference Range Should Remain Unchanged

Surks, Martin I.; Goswami, Gayotri; Daniels, Gilbert H.

doi:10.1210/jc.2005-0170

Cited by 249 publications

(195 citation statements)

References 62 publications

Supporting

Mentioning

170

Contrasting

Unclassified

Order By: Relevance

“…9 The argument against lowering the upper limit of normal for TSH values is that 22 to 28 million more Americans would be diagnosed with hypothyroidism without any clinical or therapeutic benefit from this diagnosis. 8 Our own data also show that decreasing the upper limit of the TSH reference range to 3.0 mIU/L results in more than a 4-fold increase in diagnosis of hypothyroidism among patients without history of thyroid disease seen in a tertiary medical center. 13 No clear evidence supports a benefit for intervening at these levels of TSH.…”

Section: What Is the Upper Limit Of Normal For The Serum Tsh Level?supporting

confidence: 52%

“…1,4 The clinical importance of and therapy for mild elevation of serum TSH (<10 mIU/L) 5 and the exact upper limit of normal for the serum TSH level remain subjects of debate. [6][7][8][9] When the TSH level is above 10 mIU/L, levothyroxine therapy is generally agreed to be appropriate. 5,10 However, management of patients with a serum TSH level of less than 10 mIU/L is controversial.…”

confidence: 99%

“…6,8 The strongest argument in favor of lowering the upper limit of normal for the serum TSH level is the higher level of antithyroid antibodies detected in persons with a serum TSH level between 3.0 and 5.0 mIU/L and the higher rate of progression to clinical thyroid disease. 9 After exclusion of persons with goiter, antithyroid antibodies, and a family history of thyroid disease, the mean serum TSH is 1.5 mIU/L.…”

Section: What Is the Upper Limit Of Normal For The Serum Tsh Level?mentioning

confidence: 99%

See 2 more Smart Citations

Subclinical Hypothyroidism: An Update for Primary Care Physicians

Fatourechi

2009

Mayo Clinic Proceedings

294

186

View full text Add to dashboard Cite

Subclinical hypothyroidism (SCH), also called mild thyroid failure, is diagnosed when peripheral thyroid hormone levels are within normal reference laboratory range but serum thyroid-stimulating hormone (TSH) levels are mildly elevated. This condition occurs in 3% to 8% of the general population. It is more common in women than men, and its prevalence increases with age. Of patients with SCH, 80% have a serum TSH of less than 10 mIU/L. The most important implication of SCH is high likelihood of progression to clinical hypothyroidism. The possibility that it is a cardiovascular risk factor has been a subject of debate. Large-scale randomized studies are needed for evidence-based recommendations regarding screening for mild thyroid failure and levothyroxine therapy for this condition. Currently, the practical approach is routine levothyroxine therapy for persons with a persistent serum TSH of more than 10.0 mIU/L and individualized therapy for those with a TSH of less than 10.0 mIU/L. © 2009 Mayo Foundation for Medical Education and ResearchOn completion of this article you should be able to: (1) S ubclinical hypothyroidism (SCH) is defined as a serum thyroid-stimulating hormone (TSH) level above the upper limit of normal despite normal levels of serum free thyroxine. 1 Serum TSH has a log-linear relationship with circulating thyroid hormone levels (a 2-fold change in free thyroxine will produce a 100-fold change in TSH). Thus, serum TSH measurement is the necessary test for diagnosis of mild thyroid failure when the peripheral thyroid hormone levels are within normal laboratory range. 1 The individual range for peripheral thyroid hormones is narrower than the population reference laboratory range; therefore, a slight reduction within the normal range will result in elevation of serum TSH above the normal range.Subclinical hypothyroidism or mild thyroid failure is a common problem, with a prevalence of 3% to 8% in the population without known thyroid disease. 2,3 The prevalence increases with age and is higher in women. 2 After the sixth decade of life, the prevalence in men approaches that of women, with a combined prevalence of 10%. 2 Antithyroid antibodies can be detected in 80% of patients with SCH, and 80% of patients with SCH have a serum TSH of less than 10 mIU/L.Before diagnosis of SCH, other causes of an elevated TSH level, such as recovery from nonthyroidal illness, assay variability, presence of heterophile antibodies interfering with the TSH assay, and certain cases of central hypothyroidism with biologically inactive TSH and thyroid hormone resistance, should be excluded. However, the most common cause of elevated TSH is autoimmune thyroid disease. 1 Previous radioiodine therapy, thyroid surgery, and external radiation therapy can also result in mild thyroid failure. Transient SCH may occur after episodes of postpartum, silent, and granulomatous thyroiditis. 1,4 The clinical importance of and therapy for mild elevation of serum TSH (<10 mIU/L) 5 and the exact upper limit of normal for the serum TSH ...

show abstract

Section: What Is the Upper Limit Of Normal For The Serum Tsh Level?supporting

confidence: 52%

confidence: 99%

Section: What Is the Upper Limit Of Normal For The Serum Tsh Level?mentioning

confidence: 99%

See 1 more Smart Citation

Subclinical Hypothyroidism: An Update for Primary Care Physicians

Fatourechi

2009

Mayo Clinic Proceedings

294

186

View full text Add to dashboard Cite

show abstract

“…Frequencies and percentages for calculated for the categorical variables. Subjects were further categorized according to measurements of serum TSH and free T4 levels as follows [20,21]:…”

Section: Methodsmentioning

confidence: 99%

Prevalence of subclinical hypothyroidism in adults visiting primary health-care setting in Riyadh

Eidan

Rahman

Qahtani

et al. 2018

Journal of Community Hospital Internal Medicine Perspectives

View full text Add to dashboard Cite

Background and objectives: Subclinical hypothyroidism is an asymptomatic condition with normal thyroxin and raised thyroid stimulating hormone (TSH) level. The objective of the study was to determine the prevalence of subclinical hypothyroidism in primary health care (PHC) settings in Riyadh and explore the relationship of TSH level with age, gender, family history, body mass index, and co-morbid conditions. Subjects and methods: A cross-sectional study of adult visitors to nine satellites PHC clinics in military housing in Riyadh was carried out. TSH concentration and free T4 levels were measured. Data were collected by nurses and physicians during routine clinical practice in primary care. Descriptive analysis was performed on all variables in study, and relationships were explored using chi-square, t-test, analysis of variance, and linear regression. Results: A total of 340 out of 394 participants in the study gave blood samples. Subclinical hyperthyroidism was identified in 2.1% (p = .001) and subclinical hypothyroidism in 10.3% (p = .001) of the PHC visitors. TSH levels were found to be significantly higher (p = .047) in elderly population of ≥60 years and those with family history of thyroid disease. Non-significant upward trends were noted in TSH levels with hyperlipidemia and increasing blood pressure. No overt hyperthyroidism or hypothyroidism was found in our study sample. Conclusion: Subclinical hypothyroidism has a prevalence of 10% of adults visiting PHC’s. TSH levels are higher in the elderly, which warrants screening of those aged 60 years and above.

show abstract

“…Se ha planteado la necesidad de establecer rangos de referencia específicos para cada población y así evitar una clasificación errónea de un sujeto como enfermo o sano [8][9][10] . Un pequeño descenso del valor de corte TSH para definir hipotiroidismo sube en forma exponencial el diagnóstico de la enfermedad, con el consecuente impacto en el costo de salud 11,12 .…”

unclassified