title: Thyroid volume influences serum calcitonin levels in a thyroid-healthy population: results of a 3-assay, 519 subjects study.
abstract: BACKGROUND
  We aimed to assess determinants for serum calcitonin (CT) levels and to define reference ranges for different CT immunoassays integrating thyroid ultrasonography (TUS) and conventional clinical and biochemical criteria to select the reference population.
  
  
  METHODS
  Five hundred and nineteen thyroid-healthy subjects were included in this prospective cross-sectional population study. Thyroid volume was measured by TUS, while serum CT levels were measured by three different immunoassays.
  
  
  RESULTS
  Significant interassay differences were found and the agreement between assays was poor. CT levels were higher in males than in females in all immunoassays. Using the first two assays, both gender and thyroid volume were independent determinants for CT levels. While using the third assay, one thyroid volume was the only determinant for CT levels.
  
  
  CONCLUSIONS
  Thyroid volume is a relevant determinant for CT levels. In the clinical practice, the difference of the thyroid sizes in males and females warrants gender-specific reference ranges.
authors.affiliation: Department of Nuclear Medicine and Thyroid Centre, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland. luca.giovanella@eoc.ch
authors.forename: Luca
authors.initials: L
authors.lastname: Giovanella
authors.forename: Mauro
authors.initials: M
authors.lastname: Imperiali
authors.forename: Anna
authors.initials: A
authors.lastname: Ferrari
authors.forename: Alessia
authors.initials: A
authors.lastname: Palumbo
authors.forename: Lorella
authors.initials: L
authors.lastname: Lippa
authors.forename: Andrea
authors.initials: A
authors.lastname: Peretti
authors.forename: Maria Stella
authors.initials: MS
authors.lastname: Graziani
authors.forename: Roberto
authors.initials: R
authors.lastname: Castello
authors.forename: Frederik A
authors.initials: FA
authors.lastname: Verburg
mesh_terms: D000328:Adult; D001774:Blood Chemical Analysis / Q000379:methods* / Q000592:standards*; D002116:Calcitonin / Q000097:blood*; D005260:Female; D006262:Health; D006801:Humans; D007118:Immunoassay; D057230:Limit of Detection; D008297:Male; D015999:Multivariate Analysis; D009929:Organ Size; D012016:Reference Values; D013961:Thyroid Gland / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D014463:Ultrasonography
chemical_list: D002116:Calcitonin