title: Multi-center analytical performance evaluation of the Access Hybritech® p2PSA immunoassay.
abstract: BACKGROUND
  Total PSA assays measure both complexed and non-complexed forms of PSA while free PSA assays only measure non-complexed forms. Free PSA is a mixture of isoforms including immature PSA (proPSA) with retained portions of the leader sequence (e.g. [-7], [-4], and [-2]proPSA) and nicked forms (BPSA). ProPSA isoforms in male sera have been associated with prostate cancer. This study characterized the analytical performance of a chemiluminescent immunoassay for [-2]proPSA.
  
  
  METHODS
  The Access Hybritech p2PSA assay is a sandwich immunoassay using an anti-[-2]proPSA monoclonal antibody attached to paramagnetic beads and an anti-PSA monoclonal antibody conjugated to alkaline phosphatase calibrated with recombinant [-2]proPSA. Analytical studies including sensitivity (CLSI EP17-A) and imprecision (CLSI EP5-A2) were performed.
  
  
  RESULTS
  The Access Hybritech p2PSA assay for [-2]proPSA had a dynamic range of 0.5 to 5000 pg/ml. The total CV of the assay was <7% for [-2]proPSA concentrations between 20 and 1000 pg/ml. The LOB was 0.50 pg/ml, LOD 0.69 pg/ml, and LOQ 3.23 pg/ml (20% CV). There was no hook effect up to 15,000 pg/ml. There was a <5% difference between calibrator and reagent lots and no interference from normal serum constituents.
  
  
  CONCLUSIONS
  The Access Hybritech p2PSA assay is a robust immunoassay for the measurement of serum [-2]proPSA.
authors.affiliation: Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, MD 21287, United States.
authors.forename: Lori J
authors.initials: LJ
authors.lastname: Sokoll
authors.forename: Daniel W
authors.initials: DW
authors.lastname: Chan
authors.forename: George G
authors.initials: GG
authors.lastname: Klee
authors.forename: William L
authors.initials: WL
authors.lastname: Roberts
authors.forename: Ron H N
authors.initials: RH
authors.lastname: van Schaik
authors.forename: Dorothy A
authors.initials: DA
authors.lastname: Arockiasamy
authors.forename: Dennis L
authors.initials: DL
authors.lastname: Broyles
authors.forename: Corey M
authors.initials: CM
authors.lastname: Carlson
authors.forename: Isaac A
authors.initials: IA
authors.lastname: Mizrahi
authors.forename: Tina B
authors.initials: TB
authors.lastname: Pierson
authors.forename: Jeffrey E
authors.initials: JE
authors.lastname: Tam
mesh_terms: D006801:Humans; D007118:Immunoassay / Q000379:methods*; D008163:Luminescent Measurements / Q000379:methods; D008297:Male; D017430:Prostate-Specific Antigen / Q000097:blood*; D012680:Sensitivity and Specificity
chemical_list: D017430:Prostate-Specific Antigen