title: Pre-analytical in-vitro stability of [-2]proPSA in blood and serum.
abstract: OBJECTIVE
  [-2]proPSA may discriminate prostate cancer from benign biopsy results. We characterized the pre-analytical stability of [-2]proPSA.
  
  
  METHODS
  22 volunteers, total PSA of 4.5-19.3microg/L, had blood drawn simultaneously. Baseline measurements were performed and samples were stored under various conditions prior to measurements. Freeze-thaw cycles were performed. [-2]proPSA was measured with the p2PSA automated research use only immunoassay on the Access analyzer.
  
  
  RESULTS
  Mean [-2]proPSA increases with clotting time, exceeding 10% change in recovery after 3h. In serum, [-2]proPSA values decline over time under investigated storage conditions. Serum samples kept frozen show less than 10% variation in recoveries over the course of 2 freeze-thaw cycles.
  
  
  CONCLUSIONS
  For proper measurement of [-2]proPSA, blood samples should be centrifuged within 3h of blood draw. Serum may be stored at RT or refrigerated (+4 degrees C) for a maximum of 48h and should be frozen if stored for a longer period. Two freeze-thaw cycles have no effect on [-2]proPSA stability.
authors.affiliation: Dept. of Urology, Prostate Center, University Clinic Münster, Albert-Schweitzer-Strasse 33, D-48149 Münster, Germany. semjono@uni-muenster.de
authors.forename: Axel
authors.initials: A
authors.lastname: Semjonow
authors.forename: Thomas
authors.initials: T
authors.lastname: Köpke
authors.forename: Elke
authors.initials: E
authors.lastname: Eltze
authors.forename: Beate
authors.initials: B
authors.lastname: Pepping-Schefers
authors.forename: Hilla
authors.initials: H
authors.lastname: Bürgel
authors.forename: Claude
authors.initials: C
authors.lastname: Darte
mesh_terms: D001793:Blood Preservation; D001800:Blood Specimen Collection; D006801:Humans; D007118:Immunoassay; D016014:Linear Models; D008297:Male; D011237:Predictive Value of Tests; D017430:Prostate-Specific Antigen / Q000097:blood*; D012016:Reference Values
chemical_list: D017430:Prostate-Specific Antigen