Total PSA (ПСА общий)

Prostate-specific antigen (PSA), total is used to assess disorders of the prostate, including benign prostatic hyperplasia, prostatitis, and prostate cancer. The test, also referred to as PSA total or total prostate-specific antigen, aids in risk stratification for suspected malignancy and supports differential diagnosis between malignant and nonmalignant prostatic conditions when interpreted with clinical findings and imaging. It is applied longitudinally to monitor therapeutic response in prostate cancer and to surveil for biochemical recurrence after definitive treatment. In population-based or risk-adapted preventive evaluations, total PSA contributes to early detection strategies, recognizing that clinical decisions rely on trends, age-related reference considerations, and adjunctive measures such as the free-to-total PSA ratio.

PSA is a glycoprotein serine protease produced by the prostate and released into seminal fluid, where it promotes liquefaction by cleaving seminal proteins. A small fraction enters the circulation. In serum, PSA circulates in two principal immunoreactive forms: free (unbound) PSA and PSA complexed predominantly with alpha‑1‑antichymotrypsin; their sum constitutes total PSA, the analyte measured in this assay. The free‑to‑total PSA ratio is typically lower in prostate cancer than in benign conditions and may improve discrimination when total PSA is only mildly elevated. Total PSA concentrations vary with prostate volume and increase with age. Transient elevations occur after mechanical manipulation of the gland (e.g., massage) and with activities such as bicycling; ejaculation can also raise values temporarily. Moderate increases are observed in benign prostatic hyperplasia, acute and chronic prostatitis, and urinary tract infection, whereas the principal clinical utility of total PSA testing is in detecting prostate cancer at a potentially curable stage. In several settings, a substantial proportion of patients present with advanced disease because early cancer is often asymptomatic; in some cohorts, as many as 70% are first diagnosed at stage III–IV. Digital rectal examination combined with ultrasound has limited sensitivity for early lesions, whereas PSA testing can reveal clinically silent disease. Malignant transformation disrupts epithelial integrity and vascular permeability, facilitating PSA release into blood; paradoxically, neoplastic cells synthesize less PSA per cell than normal epithelium, so PSA is specific for prostate tissue rather than for cancer per se. Higher total PSA increases the likelihood of malignancy, but mild elevations are not cancer‑specific and overlap with benign disease. Serial measurement enhances interpretation: excessive year‑to‑year PSA rise increases cancer risk, marked declines during therapy indicate treatment response, and post‑treatment increases support early recognition of recurrence.