title: Distribution of prostate specific antigen (PSA) and percentage free PSA in a contemporary screening cohort with no evidence of prostate cancer.
abstract: OBJECTIVE
  To explore the distribution of total prostate specific antigen (PSA) and percentage free/total PSA (%f/tPSA) in healthy volunteers with no clinical evidence of prostate cancer, who participated in prostate cancer screening.
  
  
  METHODS
  PSA and %f/tPSA values from 2323 men, who participated in one of three annual prostate cancer screening events between 2004 and 2006, were tabulated according to age strata of 40-49, 50-59, 60-69 and 70-79 years. Local regression smoothing plots provided a graphical display of the relation between age and PSA or %f/tPSA, respectively. All PSA and %f/tPSA analyses were repeated for each age category after excluding, respectively, the top and the bottom 10% of PSA and %f/tPSA values.
  
  
  RESULTS
  Within the entire cohort, the median PSA level was 1.0 ng/mL and the median %f/tPSA was 25%. According to the age categories the PSA level and %f/tPSA medians within the entire cohort were, respectively, 0.7, 0.9, 1.3, 1.8 ng/mL and 28.0, 26.0, 24.0 and 25.0%. Of the 2323 men, 438 (18.9%) had a PSA level of >2.5 ng/mL and 1172 (50.5%) had a %f/tPSA of < or = 25%. When either a PSA level of >2.5 ng/mL or a %f/tPSA of < or = 25% were considered, 1235 (53.2%) had one or two abnormal values. Finally, if either a PSA level of >2.5 ng/mL or %f/tPSA of < or = 15% was used, 617 (26.6%) were considered abnormal.
  
  
  CONCLUSIONS
  Half of men with no clinical evidence of prostate cancer should have PSA levels of <1.0 ng/mL and a %f/tPSA of >25%. A PSA level threshold of 2.5 ng/mL would require a biopsy in 20% of men and a %f/tPSA threshold of < or = 25% in half of the men. Alternatively, a %f/tPSA threshold of < or = 15% would decrease the probability to 15%.
authors.affiliation: Department of Urology, University Medical Centre Eppendorf, Hamburg, Germany.
authors.forename: Felix K-H
authors.initials: FK
authors.lastname: Chun
authors.forename: Georg C
authors.initials: GC
authors.lastname: Hutterer
authors.forename: Paul
authors.initials: P
authors.lastname: Perrotte
authors.forename: Andrea
authors.initials: A
authors.lastname: Gallina
authors.forename: Luc
authors.initials: L
authors.lastname: Valiquette
authors.forename: Francois
authors.initials: F
authors.lastname: Benard
authors.forename: Michael
authors.initials: M
authors.lastname: McCormack
authors.forename: Alberto
authors.initials: A
authors.lastname: Briganti
authors.forename: Constantin
authors.initials: C
authors.lastname: Ionescu
authors.forename: Claudio
authors.initials: C
authors.lastname: Jeldres
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Guay
authors.forename: Fred
authors.initials: F
authors.lastname: Saad
authors.forename: Pierre I
authors.initials: PI
authors.lastname: Karakiewicz
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood* / Q000175:diagnosis; D012044:Regression Analysis
chemical_list: D017430:Prostate-Specific Antigen