[Measurement of serum PSA values by DELFIA PSA and its clinical significance on diagnosis and follow-up of prostate cancer patients].

Serum prostate specific antigen (PSA) values detected by DELFIA PSA were evaluated for usefulness in the diagnosis and follow-up of patients with prostate cancer. The system is time-resolved fluoroimmunoassay using europium as a tracer, which has a detectable range of 0.10-500 ng/ml with a small sample volume (25 microliters) and reliable quality control data. Furthermore, serum PSA values detected by the assay were equivocal to those detected by Tandem-R PSA. From the mean +3 S.D. of serum PSA values obtained on 227 normal males, 1.98 ng/ml was decided as an upper normal level. Serum PSA values in benign prostatic hyperplasia (BPH) (n = 69) and prostate cancer (n = 86) patients were statistically higher than those in normal males. However, when 1.98 ng/ml was used as a cut-off value, the false positive rate in BPH cases elevated up to 80%. Therefore, in the differential diagnosis of prostate cancer and BPH, we recommend 11.7 ng/ml (mean + S.D. in BPH cases) as a cut-off value, in which sensitivity is 72.1%, 88.4% are true negative in BPH, and efficacy is 79.4%. Serially determined serum PSA values in following up the patients with prostate cancer were confirmed to be highly effective for diagnosing recurrence and evaluating treatment responses. These findings suggest that DELFIA PSA is a useful tool for determination of serum PSA values.