title: Comparison of serum testosterone and estradiol measurements in 3174 European men using platform immunoassay and mass spectrometry; relevance for the diagnostics in aging men.
abstract: BACKGROUND
  The limitations of serum testosterone and estradiol (E(2)) measurements using non-extraction platform immunoassays (IAs) are widely recognized. Switching to more specific mass spectrometry (MS)-based methods has been advocated, but directly comparative data on the two methods are scarce.
  
  
  METHODS
  We compared serum testosterone and E(2) measurements in a large sample of middle-aged/elderly men using a common platform IA and a gas chromatography (GC)-MS method, in order to assess their limitations and advantages, and to diagnose male hypogonadism. Of subjects from the European Male Aging Study (n=3174; age 40-79 years), peripheral serum testosterone and E(2) were analyzed using established commercial platform IAs (Roche Diagnostics E170) and in-house GC-MS methods.
  
  
  RESULTS
  Over a broad concentration range, serum testosterone concentration measured by IA and MS showed high correlation (R=0.93, P<0.001), which was less robust in the hypogonadal range (<11 nmol/l; R=0.72, P<0.001). The IA/MS correlation was weaker in E(2) measurements (R=0.32, P<0.001, at E(2) <40.8 pmol/l, and R=0.74, P<0.001, at E(2) >40.8 pmol/l). Using MS as the comparator method, IA ascertained low testosterone compatible with hypogonadism (<11 nmol/l), with 75% sensitivity and 96.3% specificity. The same parameters with IA for the detection of low E(2) (<40.7 pmol/l) were 13.3 and 99.3%, and for high E(2) (>120 pmol/l) 88.4 and 88.6%.
  
  
  CONCLUSIONS
  A validated platform IA is sufficient to detect subnormal testosterone concentrations in the diagnosis of male hypogonadism. The IA used for E(2) measurements showed poor correlation with MS and may only be suitable for the detection of high E(2) in men.
authors.affiliation: Department of Surgery and Cancer, Imperial College London, Hammersmith Campus, London, UK. ilpo.huhtaniemi@imperial.ac.uk
authors.forename: Ilpo T
authors.initials: IT
authors.lastname: Huhtaniemi
authors.forename: Abdelouahid
authors.initials: A
authors.lastname: Tajar
authors.forename: David M
authors.initials: DM
authors.lastname: Lee
authors.forename: Terence W
authors.initials: TW
authors.lastname: O'Neill
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Finn
authors.forename: György
authors.initials: G
authors.lastname: Bartfai
authors.forename: Steven
authors.initials: S
authors.lastname: Boonen
authors.forename: Felipe F
authors.initials: FF
authors.lastname: Casanueva
authors.forename: Aleksander
authors.initials: A
authors.lastname: Giwercman
authors.forename: Thang S
authors.initials: TS
authors.lastname: Han
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Kula
authors.forename: Fernand
authors.initials: F
authors.lastname: Labrie
authors.forename: Michael E J
authors.initials: ME
authors.lastname: Lean
authors.forename: Neil
authors.initials: N
authors.lastname: Pendleton
authors.forename: Margus
authors.initials: M
authors.lastname: Punab
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Silman
authors.forename: Dirk
authors.initials: D
authors.lastname: Vanderschueren
authors.forename: Gianni
authors.initials: G
authors.lastname: Forti
authors.forename: Frederick C W
authors.initials: FC
authors.lastname: Wu
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000097:blood*; D015331:Cohort Studies; D004563:Electrochemistry; D004958:Estradiol / Q000097:blood*; D005060:Europe; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007006:Hypogonadism / Q000097:blood* / Q000175:diagnosis*; D007118:Immunoassay / Q000379:methods; D008163:Luminescent Measurements; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D012709:Serum Albumin / Q000378:metabolism; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism; D013739:Testosterone / Q000097:blood*
chemical_list: D012709:Serum Albumin; D012738:Sex Hormone-Binding Globulin; D013739:Testosterone; D004958:Estradiol