title: Longitudinal changes in circulating testosterone levels determined by LC-MS/MS and by a commercially available radioimmunoassay in healthy girls and boys during the pubertal transition.
abstract: BACKGROUND
  Accurate and selective assessment of testosterone requires use of a sensitive LC-MS/MS method, especially at low levels as those seen in young children.
  
  
  METHODS
  The present longitudinal study of 20 healthy children from the Copenhagen Puberty Study followed every 6 months for 5 years evaluates the longitudinal increase in serum testosterone before, during and after pubertal onset quantified by a newly developed LC-MS/MS method in comparison with immunoassay. Testosterone concentrations in serum samples (n = 177) were determined by LC-MS/MS (detection limit 0.1 nmol/l) and by immunoassay (detection limit 0.23 nmol/l).
  
  
  RESULTS
  Serum concentrations of testosterone increased gradually with age by both methods. However, serum testosterone was quantifiable in 9/10 girls prior to pubic hair development measured with LC-MS/MS, and in 2/10 girls measured with immunoassay. In boys, testosterone was quantifiable in 10/10 boys 1 year prior to pubic hair development measured with LC-MS/MS, and only in 1/10 boys measured with immunoassay. Serum testosterone levels were quantifiable 1.5 years (range 0.5-2.5) earlier using LC-MS/MS.
  
  
  CONCLUSIONS
  Assessment of longitudinal circulating levels of serum testosterone using a selective LC-MS/MS method proved to be more sensitive in predicting early peripubertal changes in healthy children compared to levels determined by immunoassay.
authors.affiliation: Department of Growth and Reproduction, Rigshospitalet, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
authors.forename: Annette
authors.initials: A
authors.lastname: Mouritsen
authors.forename: Tue
authors.initials: T
authors.lastname: Søeborg
authors.forename: Trine Holm
authors.initials: TH
authors.lastname: Johannsen
authors.forename: Lise
authors.initials: L
authors.lastname: Aksglaede
authors.forename: Kaspar
authors.initials: K
authors.lastname: Sørensen
authors.forename: Casper P
authors.initials: CP
authors.lastname: Hagen
authors.forename: Mikkel G
authors.initials: MG
authors.lastname: Mieritz
authors.forename: Hanne
authors.initials: H
authors.lastname: Frederiksen
authors.forename: Anna-Maria
authors.initials: AM
authors.lastname: Andersson
authors.forename: Anders
authors.initials: A
authors.lastname: Juul
mesh_terms: D000293:Adolescent; D000375:Aging / Q000502:physiology*; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D013058:Mass Spectrometry; D011627:Puberty / Q000097:blood*; D011863:Radioimmunoassay; D012727:Sex Characteristics; D013739:Testosterone / Q000097:blood*
chemical_list: D013739:Testosterone