The clinical valuation of serum FPSA/FPSA in the diagnosis of prostate cancer

Objective: To explore the clinical valuation of serum of serum free prostate-specific antigen/total prostate-specific antigen (FPSA/TPSA) ratio in the diagnosis of prostate cancer with time-resolved fluoroimmunoassay. 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. Conclusion: 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 worth popularizing. (authors)