前列腺特异抗原（英语：Prostate Specific Antigen、PSA）血浆前列腺特异抗原浓度升高是提示前列腺癌的敏感监测指标；但不能作为确诊指标。

由于前列腺癌不是造成血浆前列腺特异抗原浓度升高的唯一原因；良性前列腺增生以及感染或人为因素也会引起血浆前列腺特异抗原浓度升高。在前列腺特异抗原测定的基础上，进一步细化；以提高前列腺特异抗原对前列腺癌诊断精确度引入以下概念，为临床工作提供数据鉴别：

由于前列腺特异抗原（PSA）测试药盒产自多家；t PSA，尤其是 f PSA /t PSA 、PSAD的正常值以测试实验室提供数据为准。

Prostate-specific antigen (PSA), also known as gamma-seminoprotein or kallikrein-3 (KL**), is a glycoprotein enzyme encoded in humans by the KL** gene. PSA is a member of the kallikrein-related peptidase family and is secreted by the epithelial cells of the prostate gland. PSA is produced for the ejaculate, where it liquefies semen in the seminal coagulum and allows sperm to swim freely. It is also believed to be instrumental in dissolving cervical mucus, allowing the entry of sperm into the uterus.