This research study evaluates the variability among six commercially available prostate-specific antigen (PSA) assays and its clinical implications in prostate cancer management. The analysis was conducted on serum samples from 495 patients, including individuals with prostate cancer and benign prostatic hyperplasia (BPH), comparing automated chemiluminescent assays and manual ELISA-based assays.

While all assays demonstrated strong correlation, significant differences in PSA values were observed between systems. Manual ELISA-based assays showed greater variability and poorer agreement compared to automated platforms. This inconsistency was found to impact key clinical decisions, particularly in risk stratification and monitoring of disease progression.​

The study further highlights that inter-assay variability can lead to misclassification of patient risk groups and failure to detect biochemical failure in a substantial number of cases. These findings emphasize that PSA results from different assays are not interchangeable and underscore the importance of assay consistency and standardization.