title: Testosterone reference ranges in normally cycling healthy premenopausal women.
abstract: BACKGROUND
  At present, there are no well-accepted reference ranges for serum testosterone concentrations in women.
  
  
  OBJECTIVE
  The aim of this study was to determine the reference ranges for serum testosterone and sex hormone-binding globulin (SHBG) in premenopausal women with normal menstrual cycles.
  
  
  METHODS
  We measured serum total, free, and bioavailable testosterone and SHBG concentrations in 161 healthy, normally cycling women (18-49 years). Morning blood samples were collected during follicular, mid-cycle, and luteal phases of the menstrual cycle and analyzed using validated methods. Mean, median, and weighted average hormone levels across menstrual cycle phases as well as percentiles for a typical 30-year-old woman were determined.
  
  
  METHODS
  Age-related serum levels of total, free, and bioavailable testosterone and SHBG levels in normally cycling premenopausal women.
  
  
  RESULTS
  Serum testosterone concentrations exhibited an age-related decline, whereas SHBG remained relatively stable across studied age ranges. Reference ranges for total, free, and bioavailable testosterone and SHBG were established using 5th and 95th percentiles. The estimated 5th and 95th percentiles for a 30-year-old woman were: testosterone, 15-46 ng/dL (520-1595 pmol/L); free testosterone, 1.2-6.4 pg/mL (4.16-22.2 pmol/L); calculated free testosterone, 1.3-5.6 pg/mL (4.5-19.4 pmol/L); bioavailable testosterone, 1.12-7.62 ng/dL (38.8-264.21 pmol/L); and SHBG 18-86 nmol/L. The variations of hormones and SHBG across menstrual cycle were consistent with previous literature.
  
  
  CONCLUSIONS
  Reference ranges for free, total, and bioavailable testosterone and SHBG were established in premenopausal women using validated immunoassays and an adequate number of subjects consistent with recommendations by the National Committee for Clinical Laboratory Standards. The increase in testosterone in the mid-cycle period is relatively small compared with the overall variability, so these reference ranges can be applied irrespective of the day in the menstrual cycle the sample has been taken.
authors.affiliation: Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA. braunstein@cshs.org
authors.forename: Glenn D
authors.initials: GD
authors.lastname: Braunstein
authors.forename: Richard E
authors.initials: RE
authors.lastname: Reitz
authors.forename: Akshay
authors.initials: A
authors.lastname: Buch
authors.forename: Dan
authors.initials: D
authors.lastname: Schnell
authors.forename: Michael P
authors.initials: MP
authors.lastname: Caulfield
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D005260:Female; D005498:Follicular Phase / Q000097:blood; D006801:Humans; D008183:Luteal Phase / Q000097:blood; D008597:Menstrual Cycle / Q000097:blood*; D008875:Middle Aged; D012016:Reference Values; D012738:Sex Hormone-Binding Globulin / Q000032:analysis; D013739:Testosterone / Q000097:blood*; D055815:Young Adult
chemical_list: D012738:Sex Hormone-Binding Globulin; D013739:Testosterone