Clinical evaluation of a new kit (IMX PA Dainapack) for detection of serum prostate specific antigen

: A study of the clinical utility of the IMx PA Dainapack, a new kit for detection of serum prostate specific antigen (PSA) by a fully automated enzyme immunoassay (EIA) system, was conducted. Results concerning reproducibility, dilution linearity and sensitivity were good. The excellent assay performance of this kit, particularly in terms of its high sensitivity (0.1 ng/ml), was confirmed. The upper limit of normal was determined to be 4.0 ng/ml from the mean +/- 3 S.D. (3.79 ng/ml) in healthy male controls (n = 244). Using 4.0 ng/ml as the upper limit of normal, 6 of 244 healthy male controls (2%) were positive. In various urinary diseases, 173 of 192 prostatic cancer (90%) and 46 of 112 benign prostatic hypertrophy (BPH) (41%) cases were positive. In prostatic cancer, the positive rates increased with the advance in clinical stage and in stage A the positive rate was especially high (8 of 12 (67%) were positive). On the other hand, using the BPH group as a negative control, the maximum accuracy rate for prostatic cancer had a cut-off value of 8.0 ng/ml. Thus, 8.0 ng/ml is an appropriate cut-off value differentiating prostatic cancer from BPH while 4.0 ng/ml is the cut-off value between the normal group and those with prostatic cancer (including stage A) and BPH. In the follow-up patients with prostatic cancer, serum PSA values measured by this kit reflected the effectiveness of treatment. The correlations between values obtained with the IMx PA Dainapack and 6 current kits were good (r = 0.93 to 0.99) but the values differed with the kit.(ABSTRACT TRUNCATED AT 250 WORDS)