Development and Evaluation of an Immunoglobulin Y-Based ELISA for Measuring Prostate Specific Antigen in Human Serum

Background Measurement of serum prostate specific antigen (PSA) concentrations remains one of the leading methods for diagnosing prostate cancer. We developed and evaluated an immunoglobulin Y (IgY)-based ELISA to measure total PSA (tPSA) concentrations in human serum that could be used as an alternative to commercially available in vitro diagnostic assays that rely on mouse monoclonal IgG. Methods A sandwich ELISA based on an anti-PSA IgY antibody was developed. We evaluated the ability of the anti-PSA IgY antibody to detect free and complexed PSA at the same molar ratio. The assay was optimized, and its analytical performance was verified by calculating limit of background (LoB), limit of detection (LoD), and limit of quantification (LoQ). We performed correlation and regression analyses between tPSA concentrations measured by our ELISA and those from commercial assays: Cobas 6000 (Roche Diagnostics, Warszawa, Poland) and PSA total ELISA (IBL International, Hamburg, Germany). Results LoB, LoD, and LoQ, were 0.061, 0.083, and 0.100 ng/mL, respectively, and linearity range was 0.100-3.375 ng/mL. tPSA concentrations from our IgY-based ELISA strongly correlated with those from the commercial assays. Conclusions Our IgY-based ELISA is an efficient equivalent to the above commercial assays. The use of IgY as the detecting agent could reduce the risk of false positive results, as well as decrease the overall cost of analysis.