The Biorex Diagnostics Prostate Specific Antigen (PSA) is intended for the quantitative determination of Total PSA concentration in human serum by chemiluminescent ELISA.

Prostate Specific Antigen (PSA) is a serine protease with chymotrypsin-like activity. The protein is a single chain glycoprotein with a molecular weight of 28.4 kDA. PSA derives its name from the observation that it is a normal antigen of the prostate, but is not found in any other normal or malignant tissue. PSA is released from the normal prostate and appears at low serum concentrations in healthy men. Studies with reverse transcription-PCR have shown that PSA is also expressed at a low concentration in peripheral blood cells and other tissues.