游离前列腺特异性抗原与总前列腺特异性抗原比值在前列腺癌鉴别诊断中的应用

 目的 探讨游离前列腺特异性抗原（fPSA）与总前列腺特异性抗原（tPSA）比值在前列腺癌（PCa）鉴别诊断中的意义。方法 采用电化学免疫发光技术对86例前列腺良性增生（BPH）45例PCa患者和60例健康男性体检者（正常对照组）血清fPSA和tPSA同时进行测定，并计算出fPSA／tPSA，进行统计分析。结果 BPH、PCa组tPSA水平明显高于正常对照组（P＜0.05）。PCa组和BPH组的血清tPSA差异亦有统计学意义，但当tPSA在4.0 ~ 10.0 μg／L范围时，PCa组血清fPSA／tPSA比值却明显低于BPH组（P＜0.01）。把fPSA／tPSA比值划分成8个区间，当fPSA／tPSA比值15 ％作为诊断灰区PCa诊断的临界值时，诊断的敏感性、特异性、阳性预测值、阴性预测值及正确诊断指数分别为72.8 %、67.5 %、62.5 %、82.2 %、50.2 %。结论 当血清tPSA处于诊断灰区时，联合检测fPSA／tPSA比值可明显提高tPSA对PCa早期诊断的特异性。

Application of fPSA-tPSA ratio in differential diagnosis of prostate cancer

Objective To explore the clinical value of fPSA-tPSA ratio in the differential diagnosis of prostate cancer. Methods The levels of serum total and free PSA were determined in 45 patients with prostate cancer(PCa) and 86 patients with benign prostatic hyperplasia(BPH), by electrochemiluminescence immunoassay. The ratio of free/total PSA was calculated，then the statistical analysis was performed． Results The tPSA level in disease group was significantly higher than that in normal group (P <0.05). When all pa－tients were included, both tPSA and the ratio of free/total PSA significantly differentiated between patients with PCa and patients with BPH(P <0.01). However, in men with tPSA values between 4 ~ 10 μg/L, the ratio of free/total PSA in PCa was significantly lower than that in BPH(P <0.01) where the tPSA was not(P >0.05). The value of the ratio of free/total PSA was plotted into eight parts. When the ratio of free/total PSA was 15 ％ that was as the critical value for the diagnosis of PCa with tPSA values between 4 ~ 10 μg/L． The sensitivity，specificity, positive predictive value, negative predictive value and correct diagnosis index were respectively 72.8 %, 67.5 %, 62.5 %, 82.2 %, 50.2 %. Conclusion At the diagnostic grey zone,the ratio of free/total PSA can significantly enhance the specificity of PSA for the diagnosis of PCa.