Simultaneous determination of free and total prostate-specific antigen by a magnetic particle-based time-resolved fluoroimmunoassay

Abstract

Objectives: In this paper, a novel, sensitive and rapid method to simultaneously determine the free and total prostate-specific antigen (fPSA and tPSA) in serum by combining a time-resolved fluoroimmunoassay (TRFIA) and immunomagnetic separation was described. Methods: The new approach uses magnetic particles as an immobilization matrix and means of separation, whereas the luminescent europium (Eu) and samarium (Sm) chelates are used as probes. The proposed method was evaluated via a single-step, sandwich-type TRFIA immunoassay of tPSA and fPSA as model analytes in serum. Results: A new one-step method to simultaneously detect fPSA and tPSA in less than 15 minutes was built up with the detection limits 0.006 ng/mL for fPSA and 0.05 ng/mL for tPSA. The assay ranges for fPSA and tPSA were both 0.5-100 ng/mL, whereas the average recovery of those two obtained by our original mode were 95.9% and 95.3%, respectively. The present new TRFIA method carrying larger reproducibility, higher recovery, and sensitive specificity was demonstrated to be widely acceptable. Conclusions: This simultaneous determination method containing a fast and sensitive approach can be put into an important position to screening large quantities of specimen, and be commonly applied to the clinical determination of fPSA and tPSA in human serum.