title: Measurement of total testosterone in women: comparison of a direct radioimmunoassay versus radioimmunoassay after organic solvent extraction and celite column partition chromatography.
abstract: OBJECTIVE
  To evaluate the clinical usefulness for the measurement of testosterone (T) values in the "low" female range with a direct radioimmunoassay (RIA) for total T by comparing total T values measured by this assay with values determined by conventional RIA after organic solvent extraction/column chromatography.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Victoria, Australia.
  
  
  METHODS
  Two hundred fifty-nine healthy women, aged 18-75 years, recruited from the community.
  
  
  METHODS
  Fasting serum samples were obtained and stored at -80 degrees C.
  
  
  METHODS
  Total T measurement. Total T was measured by the direct RIA method using antibody-coated tubes and iodine-labeled T tracer. For comparison, total T levels were also measured using the conventional RIA method after organic solvent (ethyl acetate:hexane [3:2]) extraction and celite column partition chromatography before RIA.
  
  
  RESULTS
  The mean T level by direct RIA was 0.76 nmol/L (median, 0.70; SD, 0.54; minimum, 0.10; maximum, 3.2). The mean difference between the two measurements (direct RIA - conventional RIA) was -0.28 (SD, 0.3). The direct RIA value was 63% (95% confidence interval, 26%-155%) of the conventional RIA estimate. For the classification of values at the lower end of the range, there was very good agreement beyond chance (kappa = 0.68-0.74) for values in approximately the lowest 10th-40th percentiles.
  
  
  CONCLUSIONS
  The direct RIA is a clinically useful assay for the study of the issue of "low" T within the female population.
authors.affiliation: The Jean Hailes Foundation, Clayton, Victoria, Australia.
authors.forename: Sonia L
authors.initials: SL
authors.lastname: Davison
authors.forename: Robin
authors.initials: R
authors.lastname: Bell
authors.forename: Joe G
authors.initials: JG
authors.lastname: Montalto
authors.forename: Ken
authors.initials: K
authors.lastname: Sikaris
authors.forename: Susan
authors.initials: S
authors.lastname: Donath
authors.forename: Frank Z
authors.initials: FZ
authors.lastname: Stanczyk
authors.forename: Susan R
authors.initials: SR
authors.lastname: Davis
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000728:Androgens / Q000032:analysis* / Q000097:blood* / Q000627:therapeutic use; D002845:Chromatography / Q000379:methods*; D003430:Cross-Sectional Studies; D007692:Diatomaceous Earth; D005260:Female; D006801:Humans; D008875:Middle Aged; D017698:Postmenopause; D017697:Premenopause; D011863:Radioimmunoassay / Q000379:methods*; D012997:Solvents; D013739:Testosterone / Q000032:analysis* / Q000097:blood* / Q000627:therapeutic use
chemical_list: D000728:Androgens; D012997:Solvents; D013739:Testosterone; D007692:Diatomaceous Earth