Keywords
Ranges
Free T4
TSH
Reference
Thyroid
How to Cite
Abstract
Background: The range of reference for TSH and free T4 vary among different populations and are likely affected by intrinsic and extrinsic factors, such as latitude, sex, race, age and nutritional status of iodine.
Purpose: To establish the range of reference of TSH and free T4 for Medellin population.
Methodology: We designed an observational prospective study. A total of 231 healthy patients between 10-65 years old from Medellin were included. TSH and free T4 levels were measured in peripheral venous blood samples. The sample required to power the study to detect a confidence interval of 90% was 120 patients. Statistical significance was defined as a p value<0.05.
Results: We found for healthy population in Medellin, values for TSH and free T4 range between 0.49 to 5.72 mU/L and 0.65 to 1.19 ng/dL, respectively.
Conclusions: For our study cohort containing patients aged between 10 to 65 years old from Medellin, Colombia, the reference values for thyroid hormones previously mentioned in the results were not statistically significant different when compared by age or sex. The intent of defining population-specific reference values was to help with the decision making and care plan for patients when assessing for thyroid disease.
References
Mullur R, Liu YY, Brent GA. Thyroid hormone regulation of metabolism. Physiol Rev. 2014;94(2):355-82. https://doi.org/10.1152/physrev.00030.2013
Jordan A, Gray R, Terkildsen M, Krockenberger M. Biological variation of total thyroxine (T4), free T4 and thyroid-stimulating hormone in 11 clinically healthy cats. J Feline Med Surg. 2021;23(6):592-7. https://doi.org/10.1177/1098612x20969485
Andersen S, Bruun NH, Pedersen KM, Laurberg P. Biologic variation is important for interpretation of thyroid function tests. Thyroid. 2003;13(11):1069-78. https://doi.org/10.1089/105072503770867237
Boucai L, Hollowell JG, Surks MI. An approach for development of age-, gender-, and ethnicity-specific thyrotropin reference limits. Thyroid. 2011;21(1):5-11. https://doi.org/10.1089/thy.2010.0092
Clinical and Laboratory Standards Institute. C45-A: measurement of free thyroid hormones; approved guideline. CLSI; 2004. https://clsi.org/media/1356/c45a_sample.pdf
Hollowell JG, Staehling NW, Flanders WD, Hannon WH, Gunter EW, Spencer CA, et al. Serum TSH, T(4), and thyroid antibodies in the United States population (1988 to 1994): National Health and Nutrition Examination Survey (NHANES III). J Clin Endocrinol Metab. 2002;87(2):489-99. https://doi.org/10.1210/jcem.87.2.8182
Builes Barrera CA, Márquez Fernández JM, Gómez Baena RM, Cárdenas Gómez ML. Valores de pruebas tiroideas (TSH y T4 libre) en una población adulta de la ciudad de Medellín, Colombia. Rev Colomb Endocrinol Diabet Metab. 2015;2(4):20-4. https://doi.org/10.53853/encr.2.4.46
Raverot V, Bonjour M, Abeillon du Payrat J, Perrin P, Roucher-Boulez F, Lasolle H, et al. Age- and sex-specific tsh upper-limit reference intervals in the general French population: there is a need to adjust our actual practices. J Clin Med. 2020;9(3):792. https://doi.org/10.3390/jcm9030792
Brabant G, Beck-Peccoz P, Jarzab B, Laurberg P, Orgiazzi J, Szabolcs I, et al. Is there a need to redefine the upper normal limit of TSH? Eur J Endocrinol. 2006;154(5):633-7. https://doi.org/10.1530/eje.1.02136
Mosso L, Margozzini P, Trejo P, Domínguez A, Solari S, Valdivia G, et al. [Thyroid stimulating hormone reference values derived from the 2009-2010 Chilean National Health Survey]. Rev Med Chil. 2013;141(1):95-103. https://doi.org/10.4067/s0034-98872013000100013
Olmedo Carrillo P, Santiago Fernández P, García Fuentes E, Ureña Fernández T, Gutiérrez Alcántara C, Sánchez-Malo C, et al. Definición de los rangos de referencia de T4 libre, TSH y tiroglobulina en sujetos sanos del Distrito Sanitario de Jaén. Endocrinol Diabetes Nutr. 2017;64(8):417-23. https://doi.org/10.1016/j.endinu.2017.06.002
Kundra P, Burman KD. The effect of medications on thyroid function tests. Med Clin North Am. 2012;96(2):283-95. https://doi.org/10.1016/j.mcna.2012.02.001
Chávarro Bermeo FE, Arteaga Diaz JM, Roth Deubel AN. Política mundial de yodación de sal: desafíos. Rev Salud Pública. 2021;23(6):1-7. https://doi.org/10.15446/rsap.v23n6.98302
Surks MI, Hollowell JG. Age-specific distribution of serum thyrotropin and antithyroid antibodies in the US population: implications for the prevalence of subclinical hypothyroidism. J Clin Endocrinol Metab. 2007;92(12):4575-82. https://doi.org/10.1210/jc.2007-1499
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