Abstract: IMMUNORADIOMETRIC ASSAY AND ITS CLINICAL APPLICATION FOR PROSTATE SPECIFIC ANTIGEN(PSA)Cui Suzhen Wang Yuxiao Liu Yibing(Department of Isotope, China Institute of Atomic Energy, Beijing 102413)ABSTRACTThe immunoradiometric assay for PSA is developed. The assay involves both monoclonal antibody and polyclonal antibody. The monoclonal antibody is labeled with 125I,and the polyclonal antibody is coated on the plastic tubes. The sensitivity of assay is 0.5 μg/L， the CVs are 1.1%-3.7% for the intraassay and 1.4%-7.0% for the interassay and the average recovery is 97.5%.The reference interval established from 100 normal men are 0-3.8 μg/L. The clinical utility of PSA is evaluated in 20 cases of benign prostatic diseases and in 9 cases of prostatic cancers. Their data of sera PSA are 24.3±13.8 μg/L and 87.0±56.3 μg/L，respectively. The correlation coefficient comparing with the PSARIA is 0.924(n=109), and the correlation coefficient comparing with the PSAEIA(Maxim Biotech) is 0.781(n=29).Key words prostate specific antigen(PSA) prostate cancer(PCa) immunoradiometric assay(IRMA)