title: Free / total prostate specific antigen ratio for prostate cancer detection: a prospective blind study.
abstract: BACKGROUND
  We conducted this prospective study to evaluate the ability of the percentage of free PSA (% fit PSA) to improve the specificity of prostate cancer (PC) detection.
  
  
  METHODS
  Seven hundred and eighty-five patients with serum PSA levels between 4 and 25 ng/ml underwent sextant biopsies of the prostate. The % f/t PSA was analyzed for the sensitivity, specificity and positive predictive values.
  
  
  RESULTS
  The mean % f/t PSA of the 169 patients with PC was 18.0 +/- 7.7 and was significantly (p < 0.0001) lower than that of the 616 patients who had histologically benign biopsy specimens, with a mean % f/t PSA of 26.6 +/- 9.7. Using 30% f/t PSA as the cut-off eliminated 34.4 % of the negative biopsies while still detecting 93.4% of the carcinomas.
  
  
  CONCLUSIONS
  The optimal cut-off value of 30% f/t PSA may be applied as reference using the Cis bio international assay for PC detection.
authors.affiliation: Division of Urology, Department of Surgery, Taichung Veterans General Hospital, School of Medicine, National Yang-Ming University, Taiwan, ROC.
authors.forename: Chi-Rei
authors.initials: CR
authors.lastname: Yang
authors.forename: Chung-Knang
authors.initials: CK
authors.lastname: Su
authors.forename: Kun-Yuan
authors.initials: KY
authors.lastname: Chiu
authors.forename: Hao-Chung
authors.initials: HC
authors.lastname: Ho
authors.forename: Yen-Chuan
authors.initials: YC
authors.lastname: Ou
authors.forename: Cheng-Li
authors.initials: CL
authors.lastname: Cheng
authors.forename: Huei
authors.initials: H
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D017430:Prostate-Specific Antigen / Q000097:blood*; D011469:Prostatic Diseases / Q000097:blood / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000473:pathology; D011471:Prostatic Neoplasms / Q000097:blood / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D012372:ROC Curve; D012680:Sensitivity and Specificity; D016037:Single-Blind Method; D014463:Ultrasonography
chemical_list: D017430:Prostate-Specific Antigen