探讨总前列腺特异性抗原（T－PSA）与游离前列腺特异性抗原（FPSA）的比值（F／TPSA）对T－PSA在4～10ng／ml之间的良性前列腺增生（BPH）和前列腺癌（PC）鉴别诊断的意义。采用放射免疫法对281例患者的T－PSA和FPSA进行测定，并计算F／TPSA，其中T－PSA在4～10ng／ml的PC和BPH患者分别是10例和51例。结果：PC组和BPH组的T－PSA分别是622ng／ml和6．14ng／ml，两组相比无显著差异（P＞0.O5）；而F／TPSA比值分别是0．11和0．21，两组相比有显著性差异（P＜0．01），当F／TPSA阈值小于0．15～0．20时，诊断的敏感性和特异性分别是70％～90％和88％～67％。F／TPSA有助于鉴别TPSA在4～10ng／ml之间的BPH和PC，具有较高的敏感性和特异性，可以减少不必要的活检。 To investigate the relationship between the ratio of total prostate specific antigen (T-PSA) to free prostate specific antigen (FPSA) (F / TPSA) in benign prostatic hyperplasia (BPH) and prostate cancer PC) the significance of differential diagnosis. T-PSA and FPSA were measured by radioimmunoassay in 281 patients and F / TPSA was calculated. T-PSA was found in 10 and 51 patients with PC and BPH ranging from 4 to 10 ng / ml, respectively. Results: The T-PSA of PC group and BPH group were 622ng / ml and 6.14ng / ml respectively, there was no significant difference between the two groups (P> 0.05), while the F / TPSA ratios were 0.11 and 0 .21, there was significant difference between the two groups (P <0.01). When the threshold of F / TPSA is less than 0.15 ~ 0.20, the sensitivity and specificity of diagnosis are 70% ~ 90% and 88 % ~ 67%. F / TPSA helps to identify BPH and PC with TPSA between 4 and 10 ng / ml with high sensitivity and specificity to reduce unnecessary biopsies.