Objective To explore the clinical valuation of serum free prostate-specific antigen/total prostate-specific antigen(FPSA/TPSA) ratio in the diagnosis of prostate cancer with time-resolved fluoroim-munoassay.

Methods Selected randomly 115 patients with benign prostatic hyperplasia and 58 patients with prostate cancer, sixty healthy physical examinees were chosen as normal control. Serum TPSA, FPSA and FPSA/TPSA ratio were measured with time-resolved fluoroimmunoassay.

Results When TPSA was between 4.0- 45.5 μg/L, there was the rang of overlapping of TPSA in benign prostatic hyperplasia and prostate cancer patients. TPSA couldn't be a differential mark for the two conditions(t=1.76, P>0.05). But there were significant differences in the FPSA/TPSA ratio between the two conditions(t=2.74, P < 0.05). When the reference value was FPSA/TPSA≤0.15 in differential diagnosis of prostate cancer, it maintained a high sensitivity(91.5%), improved specificity(78.6%) and reliability(79.8%). It also improved positive predictive value(82.5%) and negative predictive value(96.5%) to a certain extent.

Conclusions FPSA/TPSA ratio could make up for the shortage of only TPSA and improved the early detection rate of prostate cancer. It also reduced unnecessary biopsy and worth popularizing.