Acronym for “Prostate-Specific Antigen” – in Portuguese, prostate-specific antigen. PSA is a substance normally produced by the prostate gland, whose function is to liquefy semen, facilitating the movement of sperm.
A small part of the PSA produced by prostate cells is released into the bloodstream, where it can be measured by a blood test. PSA levels may be increased in some prostate conditions, including organ infections and benign prostatic hyperplasia. In addition, clinical examination of the prostate, performed through digital rectal examination, can also increase blood levels of PSA.
However, the PSA level is often elevated in cases of prostate cancer, which is why the test is used for screening and early detection of the disease. Furthermore, PSA is an important prognostic factor for prostate cancer, as well as its changes over time (called PSA kinetics and which comprise the PSA velocity and/or its doubling time). Finally, PSA is used in the post-treatment follow-up of prostate cancer, helping to early detect eventual recurrences of the disease.
To learn more about prostate cancer, see the “Prostate Cancer” section.