title: Determination of thyrotropin reference values in an adult Mexican population.
abstract: OBJECTIVE
  The upper limit of TSH reference level is controversial. The purpose of our study was to determine TSH reference values in a Mexican population in accordance with the National Academy of Clinical Biochemistry (NACB) criteria and in correlation with thyroid ultrasound (US) examination.
  
  
  METHODS
  The study was conducted in volunteers with no known thyroid disease. We recruited 482 subjects, most of them medical or administrative staff from our hospital. They answered a questionnaire on demographic data, family history, co-morbidities, and drug use. Their thyroid hormone levels and thyroid antibodies were determined, and a complete physical examination and thyroid US were performed. The population used to establish the TSH reference intervals was selected according to the NACB criteria and their normal thyroid structural and echogenic characteristics in US examination.
  
  
  RESULTS
  Among 482 subjects (209 males) with a median age of 26 years, prevalence rates of TPOAb and TgAb were 9.3% and 10.3% respectively. Mean TSH level in the overall population was 1.90±1.94, with a 97.5th percentile of 6.76 mIU/L. The reference population was limited to 282 subjects (41.5% were excluded) with a mean TSH of 1.86±1.63 and a 97.5th percentile of 4.88 mIU/L. No sex difference was found (p=0.287). Median urinary iodine level in the reference population was 267 μg/L IQR (161.3-482.5).
  
  
  CONCLUSIONS
  The TSH reference interval in the reference population was 0.71 (CI 0.65-0.77) to 4.88 mIU/L (CI 4.5-5.3); these limits may be influenced by iodine nutritional status in this population.
authors.affiliation: Department of Internal Medicine, Instituto Nacional de Ciencias Médicas, Y Nutrición "Salvador Zubirán", Vasco de Quiroga #15, Col. Sección XVI, Tlalpan, México, DF CP: 14000, Mexico. Electronic address: afcalatrava@yahoo.com.
authors.forename: Armando
authors.initials: A
authors.lastname: Flores-Rebollar
authors.affiliation: Department of Internal Medicine, Instituto Nacional de Ciencias Médicas, Y Nutrición "Salvador Zubirán", Vasco de Quiroga #15, Col. Sección XVI, Tlalpan, México, DF CP: 14000, Mexico.
authors.forename: Lidia
authors.initials: L
authors.lastname: Moreno-Castañeda
authors.affiliation: Department of Internal Medicine, Instituto Nacional de Ciencias Médicas, Y Nutrición "Salvador Zubirán", Vasco de Quiroga #15, Col. Sección XVI, Tlalpan, México, DF CP: 14000, Mexico.
authors.forename: Norman S
authors.initials: NS
authors.lastname: Vega-Servín
authors.affiliation: Department of Nuclear Medicine, Instituto Nacional de Ciencias Médicas, Y Nutrición "Salvador Zubirán", Vasco de Quiroga #15, Col. Sección XVI, Tlalpan, México, DF CP: 14000, Mexico.
authors.forename: Guadalupe
authors.initials: G
authors.lastname: López-Carrasco
authors.affiliation: Department of Nuclear Medicine, Instituto Nacional de Ciencias Médicas, Y Nutrición "Salvador Zubirán", Vasco de Quiroga #15, Col. Sección XVI, Tlalpan, México, DF CP: 14000, Mexico.
authors.forename: Aída
authors.initials: A
authors.lastname: Ruiz-Juvera
mesh_terms: D000328:Adult; D001323:Autoantibodies / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007455:Iodine / Q000172:deficiency / Q000652:urine; D008297:Male; D008800:Mexico / Q000453:epidemiology; D010564:Personnel, Hospital; D010808:Physical Examination; D012016:Reference Values; D013961:Thyroid Gland / Q000000981:diagnostic imaging; D013963:Thyroid Hormones / Q000097:blood; D013972:Thyrotropin / Q000097:blood* / Q000276:immunology; D055815:Young Adult
chemical_list: D001323:Autoantibodies; D013963:Thyroid Hormones; C056626:thyroid microsomal antibodies; D013972:Thyrotropin; D007455:Iodine
keywords: Anticuerpos antiperoxidasa tiroideo; Anticuerpos antitiroglobulina; Reference values; Thyroglobulin antibody; Thyroid peroxidase antibody; Thyroid ultrasound; Thyrotropin; Tirotropina; Ultrasonido tiroideo; Valores de referencia