Progress in standardization of immunoassays for prostate-specific antigen

Area of Science:

• Biochemistry
• Clinical Chemistry
• Oncology

Background:

• Prostate-specific antigen (PSA) assays are crucial for prostate cancer diagnosis and management.
• Significant inter-assay variability exists for PSA measurements, particularly for free PSA (fPSA).
• Standardization of PSA assays is needed to improve diagnostic accuracy and patient care.

Purpose of the Study:

• To evaluate a novel calibrator composed of prostate-specific antigen-alpha 1-antichymotrypsin (PSA-ACT) and free PSA (fPSA).
• To assess the calibrator's ability to reduce variation in PSA control serums.
• To determine the suitability of the calibrator for international standardization of PSA assays.

Main Methods:

• Development of a calibrator with a 90:10 ratio of PSA-ACT to fPSA.
• Testing the calibrator's performance across nine different PSA assays with varying fPSA levels.
• Recalibration of control serums using the new calibrator.

Main Results:

• The PSA-ACT/fPSA calibrator reduced mean variation in control serums from 28% to 9%.
• The lyophilized calibrator demonstrated good stability.
• The calibrator effectively harmonized results across diverse PSA assays.

Conclusions:

• A 90:10 PSA-ACT/fPSA calibrator significantly improves the consistency of PSA measurements.
• The stability and efficacy of the calibrator make it a strong candidate for international PSA assay standardization.
• This standardization effort can lead to more reliable prostate cancer screening and monitoring.