Methods: 692 middle-aged and senior males were selected and their serum was seperated.PSA concentration was determined with enzyme linked immunosorbent assay(ELISA)on the standard curve.

• 方法:以692例中老年男性为研究对象,取样后分离血清,采用双抗体夹心法,根据标准曲线计算出样品的浓度;