title: Prostate cancer screening: clinical impact of WHO calibration of Beckman Coulter Access prostate-specific antigen assays.
abstract: BACKGROUND
  The goal of this study was to evaluate the clinical impact of using the same total prostate-specific antigen (tPSA) and free PSA (fPSA) assays calibrated with World Health Organization (WHO) materials or with Hybritech Tandem-R calibrator.
  
  
  METHODS
  From the initial correlation study that included 150 patients, the clinical impact of the WHO calibration was simulated using a large cohort (n=4548) of referred patients. Interim reports of the European Study of Screening for Prostate Cancer (ERSPC) were used to evaluate the clinical outcomes of patients and the risk of prostate cancer (PCa).
  
  
  RESULTS
  WHO calibration of tPSA assays leads to a reduction of about 20% in measured results (tPSA WHO=0.81 tPSA Hybritech+0.04; fPSA WHO=0.78 fPSA Hybritech+0.00; %fPSA WHO=0.92 %fPSA Hybritech+0.00). The simulation showed that the WHO calibration is associated with a risk of missing 15% of PCa.
  
  
  CONCLUSIONS
  The discrepancies between the two calibrations lead to significant clinical misinterpretation with decreased detection of PCa if tPSA cut-off thresholds are not adjusted.
authors.affiliation: Department of Clinical Biochemistry, Cliniques Universitaires Saint-Luc, Brussels, Belgium. catherine.fillee@uclouvain.be
authors.forename: Catherine
authors.initials: C
authors.lastname: Fillée
authors.forename: Bertrand
authors.initials: B
authors.lastname: Tombal
authors.forename: Marianne
authors.initials: M
authors.lastname: Philippe
mesh_terms: D002138:Calibration; D019411:Clinical Laboratory Techniques / Q000295:instrumentation* / Q000379:methods / Q000592:standards*; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000295:instrumentation / Q000379:methods / Q000592:standards; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood* / Q000175:diagnosis*; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014944:World Health Organization
chemical_list: D017430:Prostate-Specific Antigen