title: Inhibin B reference data for fertile and infertile men in Northeast America.
abstract: OBJECTIVE
  To determine normative levels of inhibin B and examine levels in relationship to FSH, sperm count, and motility in a cohort of fertile and infertile men from the Northeast United States.
  
  
  METHODS
  Prospective comparative study of inhibin B levels in fertile and infertile patient groups.
  
  
  METHODS
  Tertiary academic referral center.
  
  
  METHODS
  Fertile men were recruited among those presenting for elective vasectomy. Men being evaluated for infertility were also recruited within the same practice.
  
  
  METHODS
  Serum collection.
  
  
  METHODS
  FSH and inhibin B levels were measured in serum samples.
  
  
  RESULTS
  A total of 55 fertile and 85 presenting for infertility evaluations were recruited. The mean serum inhibin B level was significantly higher in the fertile (138 pg/mL) than infertile group (78 pg/mL). Inhibin B levels correlated positively (R(2) = 0.27) and FSH correlated negatively (R(2) = 0.33) with total sperm concentration. General linear model multiple regression demonstrated that the FSH and inhibin B were equally predictive of sperm concentration.
  
  
  CONCLUSIONS
  Inhibin B levels in fertile men and infertile men in Northeast America were similar but not identical to those reported in other geographic regions. Both inhibin B and FSH are useful markers of spermatogenesis.
authors.affiliation: The Alpert Medical School of Brown University, Providence, Rhode Island, USA.
authors.forename: Gavin M
authors.initials: GM
authors.lastname: Myers
authors.forename: Geralyn M
authors.initials: GM
authors.lastname: Lambert-Messerlian
authors.forename: Mark
authors.initials: M
authors.lastname: Sigman
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood*; D002624:Chemistry, Clinical / Q000592:standards*; D005298:Fertility / Q000502:physiology*; D005640:Follicle Stimulating Hormone / Q000097:blood; D006801:Humans; D007248:Infertility, Male / Q000097:blood*; D007265:Inhibins / Q000097:blood*; D016014:Linear Models; D008297:Male; D009511:New England; D011237:Predictive Value of Tests; D012016:Reference Values; D013076:Sperm Count; D013091:Spermatogenesis / Q000502:physiology; D014659:Vasectomy
chemical_list: D015415:Biomarkers; C422364:inhibin B; D007265:Inhibins; D005640:Follicle Stimulating Hormone