Analytical issues on prostate-specific antigen in relation to prostate cancer screening

Area of Science:

• Clinical chemistry
• Biomarker analysis
• Prostate cancer diagnostics

Background:

• Prostate-specific antigen (PSA) is a key biomarker for prostate cancer screening.
• The European Randomized Study of Screening for Prostate Cancer (ERSPC) utilizes PSA assays for early detection.
• Evaluating assay performance is crucial for reliable screening outcomes.

Purpose of the Study:

• To assess the analytical performance of the Hybritech Tandem-E PSA assay.
• To determine the assay's reliability for prostate cancer screening within the ERSPC.
• To evaluate factors affecting PSA measurement accuracy and precision.

Main Methods:

• Analysis of assay imprecision and accuracy.
• Investigation of pre-analytical variables including specimen handling and storage.
• Assessment of long-term reagent stability and calibration using the Stanford 90:10 PSA Calibrator.

Main Results:

• Total PSA demonstrated marker stability under recommended storage conditions.
• No significant differences were observed between same-day and next-day sample analysis.
• Excellent day-to-day precision was achieved (CVs of 4.9% and 4.2%).
• Minimal variation was noted across multiple reagent batches over four years.

Conclusions:

• The Hybritech Tandem-E PSA assay provides reliable, long-term performance for prostate cancer screening.
• Assay results are consistent and precise, supporting its clinical utility.
• Further investigation into potential discrepancies with true PSA values is warranted.