title: The f/t-PSA ratio in diagnosis of in-patients and out-patients: a unitary cutoff value is not useful!
abstract: OBJECTIVE
  In the prostate specific antigen (PSA) range of 4-10 ng/ml after a negative digital rectal examination, the PSA value indicates a lack of specificity with a carcinoma detection rate of roughly 20%. To improve the biopsy/carcinoma ratio, the interdisciplinary consensus recommends free PSA (fPSA) measurement. This does not take into account the pre-analysis when the cutoff value is established for biopsy indication.
  
  
  METHODS
  In the present study, an in-patient cohort whose blood samples were immediately analysed was compared with an out-patient cohort whose sample processing was delayed by between 24 and 48 h.
  
  
  RESULTS
  The in-patient cohort comprises 382 patients with 99 prostate carcinomas, the out-patient cohort 987 patients with 235 carcinomas. In the in-patient cohort a sensitivity of 90% with a cutoff value of 25% for the f/t-PSA ratios is achieved with the theoretical possibility of reducing the number of punch biopsies by 34.6%. A sensitivity of 90% in the out-patient cohort necessitates a cutoff value of 18% for the f/t-PSA ratios. The specificity is 35.3% with a possible biopsy reduction of 29.1%.
  
  
  CONCLUSIONS
  The cutoff values from cohorts with an immediate fPSA measurement cannot be adopted for a typical out-patient cohort whose analyses are delayed. On the contrary, an individual adjustment is necessary which corresponds to the pre-analysis.
authors: Department of Urology and Urooncology, University of Essen Medical School, Hufelandstr. 55, 45122 Essen, Germany. christof.boergermann@uk-essen.de
authors: C
authors: C
authors: Börgermann
authors: A
authors: A
authors: Swoboda
authors: H-J
authors: HJ
authors: Luboldt
authors: F
authors: F
authors: vom Dorp
authors: H
authors: H
authors: Rübben
mesh_terms: D006801:Humans; D007297:Inpatients; D008297:Male; D008875:Middle Aged; D010045:Outpatients; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood*; D013997:Time Factors
chemical_list: D017430:Prostate-Specific Antigen