Total PSA
PSA
PSA is a specific protein that is produced in the prostate gland and is used to diagnose oncological and inflammatory diseases of the prostate. PSA is synthesized by the cells of the excretory ducts of the prostate gland and is necessary for the dilution of the ejaculate. Outside the prostate, the site of PSA production is the paraurethral glands and the breast.
The prostate-specific antigen enters the bloodstream in small amounts and is detected in the form of three fractions:
- Free
- Bound to alpha-1-antichymotrypsin
- Bound to alpha-2-macroglobulin
It is extremely difficult to determine the bound fraction by publicly available laboratory means, since PSA is located "inside" these chemical complexes. For this reason, only PSA-General and PSA-free are defined. These two tests together are of great diagnostic value.
The blood level of total PSA gradually increases with age (from 2.0 ng/m to 6.5 ng/ml), and any mechanical effect on the prostate or its disease leads to the release of antigen into the bloodstream. However, a concentration of more than 10 ng/ml indicates the likelihood of benign prostatic hypertrophy (BPH). A total PSA value of over 30 ng/ml is an indicator of the risk of prostate cancer. Most men with a total PSA level in excess of 50 ng/ml have regional metastases in the lymph nodes of the pelvis. A concentration above 100 ng/ml is an indicator of the presence of distant metastases.
The advantage of this method is the ability to identify cancer at a stage when there are practically no clinical manifestations. It is recommended to take two tests at the same time: general PSA and free PSA.
Attention! The test is done no earlier than 7 days after prostate massage, transrectal ultrasound, or finger rectal analysis, as a false positive result is possible.
Read also: "Prostate-specific antigen and men's health," "Men's health: myths and reality," profile "Men's health."