Its function is to keep the seminal fluid fluid after ejaculation, so that the spermatozoa can move more easily in the female genital tract. PSA is, therefore, a physiological substance normally produced even by healthy men.
Benign prostate antigen is readily detectable in a small blood sample, usually taken from a vein in the patient's forearm.
, a "benign prostatic hypertrophy or prostate cancer.PSA is a specific marker of the organ, but not of the pathologies that affect it: high values could suggest both the presence of benign conditions (a prostatitis, a benign prostatic hyperplasia, etc.), as well as of neoplastic processes of the prostate. For this reason, the clinical value of PSA has long been at the center of scientific discussions.
The assay of PSA in plasma has a low degree of specificity: when its levels exceed 4 ng per ml of blood, most likely something is wrong with the prostate, but in the absence of further diagnostic investigations it is impossible to establish with certainty the benignity or the malignancy of the condition.
If the suspicion of cancer is confirmed by other diagnostic tests, the PSA measurement is a good indicator of tumor extension. In particular, when the PSA is only slightly increased or even normal, the tumor is unlikely to be very extensive.
To improve the diagnostic specificity of the PSA, in cases where the limit value is exceeded, the free-PSA is also measured.
