It is used for quantitative detection of total prostate specific antigen (t-PSA) in human serum in vitro. Total prostate specific antigen (t-PSA) is a single chain glycoprotein with a molecular weight of 32KD, secreted by prostate epithelial cells. It is a serine protease similar to chymotrypsin. Under normal circumstances, PSA secretes semen and plays a physiological role in the division of seminal vesicle and the liquefaction of semen. In normal condition, only a very low level of PSA exists in the blood. The increase of PSA concentration in serum indicates pathological changes or trauma of prostate. PSA levels are elevated in the vast majority of prostate cancer patients. This kit is used for auxiliary diagnosis, efficacy evaluation and dynamic monitoring of disease progress of prostate patients.