PSA (Free)

Prostate-Specific Antigen (PSA) is a protein produced by cells in the prostate gland (normal and cancerous). Elevated blood levels can indicate prostate cancer, but also benign conditions like benign prostatic hyperplasia (BPH) or prostatitis. PSA testing is used for prostate cancer screening and monitoring, though its interpretation requires consideration of age, prostate size, trends over time (velocity), and free/total PSA ratio to improve specificity.

Since women don’t have a prostate, PSA usually has little clinical significance and isn’t routinely measured. However, low but measurable PSA can be produced by periurethral (Skene’s) glands, and it’s being studied as an emerging marker of androgen excess (hyperandrogenism), such as in PCOS, hirsutism, or Cushing’s syndrome.