[Rinsho Byori 50 : 202-206, 2002]

Improvement of Total Prostate Specific Antigen(PSA) Assay from
the "Skewed Molar-Response" to the "Equimolar-Response" by
Utilizing anti Free-PSA Monoclonal Antibodies

Emi KIMURA*1, Kyoichi MATSUMOTO*2 and Tomohiro SAMORI, MD*3

Prostate specific antigen(PSA) is widely used as a marker for screening and monitoring prostate cancer. However, there are several assay methods, which often give different PSA values for the same patient sample. A possible cause of these discrepancies might be the varied immunoreactivity with free-PSA and complex-PSA among methods.
This study revealed that pre-treatment of samples with anti-free-PSA monoclonal antibodies improved polyclonal antibodies-based non equimolar PSA assay to equimolar assay.
This might be achieved by that the monoclonal antibodies bind to free-PSA and then change its reactivities with polyclonal antibodies to those similar to complex-PSA.