OBJECTIVE: Development of an ultrasensitive immunoassay for serum PSA involving conventional detection probes. DESIGN AND METHODS: The assay involves a polyclonal antibody immobilized in microtitration wells and a monoclonal antibody labeled with horseradish peroxidase. In a one-step assay, the enzymatic activity of the bound detection antibody is monitored by the addition of hydrogen peroxide/tetramethylbenzidine substrate reagent followed by spectrophotometric quantification of the conversion product. RESULTS: The assay has a lower detection limit of 0.003 micrograms/L, biological detection limit of 0.009 micrograms/L, and intra- and interassay CVs of 8.2% and 10.5% at PSA concentrations of 0.022 and 0.065 micrograms/L, respectively. The recovery of the assay averaged 104% and it demonstrated a dilution linearity down to at least 0.01 micrograms of PSA/L. Results of comparison data correlated well with those obtained by a well established enzyme immunoassay. The serum PSA concentrations were < 0.012 micrograms/L in the majority of patients (53.8%) who had undergone radical prostatectomy. CONCLUSIONS: This assay is well suited for post-surgical monitoring of PSA in patients with prostate cancer.
OBJECTIVE: Development of an ultrasensitive immunoassay for serum PSA involving conventional detection probes. DESIGN AND METHODS: The assay involves a polyclonal antibody immobilized in microtitration wells and a monoclonal antibody labeled with horseradish peroxidase. In a one-step assay, the enzymatic activity of the bound detection antibody is monitored by the addition of hydrogen peroxide/tetramethylbenzidine substrate reagent followed by spectrophotometric quantification of the conversion product. RESULTS: The assay has a lower detection limit of 0.003 micrograms/L, biological detection limit of 0.009 micrograms/L, and intra- and interassay CVs of 8.2% and 10.5% at PSA concentrations of 0.022 and 0.065 micrograms/L, respectively. The recovery of the assay averaged 104% and it demonstrated a dilution linearity down to at least 0.01 micrograms of PSA/L. Results of comparison data correlated well with those obtained by a well established enzyme immunoassay. The serum PSA concentrations were < 0.012 micrograms/L in the majority of patients (53.8%) who had undergone radical prostatectomy. CONCLUSIONS: This assay is well suited for post-surgical monitoring of PSA in patients with prostate cancer.
Authors: Teemu D Laajala; Heikki Seikkula; Fatemeh Seyednasrollah; Tuomas Mirtti; Peter J Boström; Laura L Elo Journal: Sci Rep Date: 2016-11-02 Impact factor: 4.379