Nucleic acid detection immunoassay for prostate-specific antigen based on immuno-PCR methodology

Area of Science:

• Biochemistry
• Immunology
• Oncology

Background:

• Standard prostate-specific antigen (PSA) assays lack the sensitivity to detect low PSA levels post-radical prostatectomy.
• Biochemical recurrence in prostate cancer patients is often delayed due to assay limitations.
• Current ultrasensitive PSA assays struggle with day-to-day imprecision, hindering kinetic analysis.

Purpose of the Study:

• To develop a highly sensitive immuno-PCR assay for total PSA.
• To overcome the limitations of existing assays in detecting low PSA concentrations.
• To enable earlier detection of biochemical recurrence in prostate cancer patients.

Main Methods:

• A 2-site immunometric assay using monoclonal antibodies labeled with DNA and paramagnetic microparticles was developed.
• Quantification involved DNA labeling, microparticle capture, and PCR amplification.
• Analytical performance was characterized and compared to a commercial PSA assay.

Main Results:

• The developed assay demonstrated a limit of quantification of 0.65 ng/L, over 10 times lower than ultrasensitive assays.
• Assay linearity was observed in the range of 0.25-152.0 ng/L with low imprecision (<15.2%).
• High accuracy was confirmed through recovery studies and comparison with a commercial assay (correlation coefficient 0.996).

Conclusions:

• The novel immuno-PCR assay provides accurate and precise measurements of serum PSA.
• The assay's high sensitivity allows for reliable detection of sub-nanogram-per-liter PSA concentrations.
• This assay has the potential to significantly improve the monitoring of prostate cancer recurrence.