Significant Issues Derived from the Choice of a PSA Test for Measuring PSA in Serum: Comparison of IMx Enzyme immunoassay and ELSA Immunoradiometric Assay / 대한비뇨기과학회지

ABSTRACT

Prostate specific antigen (PSA) has become established as the most useful serological marker for monitoring patients with prostate cancer. However, the benefits of serum PSA values are controversial in screening procedures for prostate cancer due to the rather low specificity of PSA test. To determine if different assays yield comparable results, we compared the IMx PSA enzyme immunoassay and the ELSA PSA monoclonal immunoradiometric assay. We analyzed 72 serum specimens from 68 patients with prostatic disease (12 patients with cancer, 47 benign hyperplasia and 9 prostatitis) and 13 from normal controls by both assays. Results from the assays revealed close linear correlation but the ELSA PSA assay yielded values 1.5 times those of the IMx PSA assay In 13 patients with histologically diagnosed benign prostatic hyperplasia, number of patient with PSA value over l0 ng/ml measured by IMx and ELSA assay were 2(15% ) and 4(31%), respectively. We conclude that the proportional bias between assays demonstrates a need for improved standardization of PSA assays.