title: Sex- and Age-Specific Reference Values and Cutoff Points for TPOAb: Tehran Thyroid Study.
abstract: BACKGROUND
  Current guidelines used for establishing reference intervals for thyroid peroxidase antibodies (TPOAb), recommended by the National Academy of Clinical Biochemistry, have been a matter of controversy. The present study sought to determine TPOAb reference intervals for different age and sex groups, as well as the TPOAb cutoff points for subclinical and overt hypothyroidism in an iodine-sufficient population.
  
  
  METHODS
  This cross-sectional study was conducted within the framework of the prospective Tehran Thyroid Study (TTS), in which 4174 healthy euthyroid individuals were followed for 10 years. Thyroid function tests and TPOAb were assessed.
  
  
  RESULTS
  The mean age ± standard deviation of participants was 39.3 ± 15.2 years. Estimated reference intervals for TPOAb corresponding to the 2.5th and 97.5th percentiles were 1.5-32.8 and 2.1-35 IU/mL in males and females, respectively. There were no significant variations in the different age groups in either sex. The optimal cutoff points for TPOAb were 18.38 and 14.77 IU/mL for predicting clinical and subclinical hypothyroidism, respectively.
  
  
  CONCLUSIONS
  This study establishes the reference intervals and the optimal cutoff points for TPOAb in an iodine-sufficient population.
authors.affiliation: 1 Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences , Tehran, Iran .
authors.forename: Atieh
authors.initials: A
authors.lastname: Amouzegar
authors.affiliation: 1 Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences , Tehran, Iran .|2 Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences , Tehran, Iran .
authors.forename: Mahmood
authors.initials: M
authors.lastname: Bakhtiyari
authors.affiliation: 2 Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences , Tehran, Iran .
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Mansournia
authors.affiliation: 1 Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences , Tehran, Iran .
authors.forename: Ali
authors.initials: A
authors.lastname: Etemadi
authors.affiliation: 1 Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences , Tehran, Iran .
authors.forename: Ladan
authors.initials: L
authors.lastname: Mehran
authors.affiliation: 3 Prevention of Metabolic Disorder Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences , Tehran, Iran .
authors.forename: Maryam
authors.initials: M
authors.lastname: Tohidi
authors.affiliation: 1 Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences , Tehran, Iran .
authors.forename: Fereidoun
authors.initials: F
authors.lastname: Azizi
mesh_terms: D000328:Adult; D001323:Autoantibodies / Q000097:blood*; D001324:Autoantigens / Q000276:immunology*; D015415:Biomarkers / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007037:Hypothyroidism / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D007453:Iodide Peroxidase / Q000276:immunology*; D007492:Iran; D033862:Iron-Binding Proteins / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012016:Reference Values; D055815:Young Adult
chemical_list: D001323:Autoantibodies; D001324:Autoantigens; D015415:Biomarkers; D033862:Iron-Binding Proteins; C056626:thyroid microsomal antibodies; C056658:TPO protein, human; D007453:Iodide Peroxidase