Use

In general, serum PSA levels increase due to physical changes to prostate architecture caused by trauma, infection, inflammation, prostate manipulation, benign prostatic hypertrophy (BPH), or malignancy. The sensitivity of PSA levels to these changes serves as the basis for the clinical use of the test. The PSA concentration in the serum of healthy men is a millionfold lower than that in seminal fluid. PSA in seminal fluid is predominantly free or uncomplexed. In serum, the majority of PSA is bound to inhibitors, including α₁-antichymotrypsin (ACT) and α₂-macroglobulin (A2M). Measured total PSA consists of free and ACT-bound, since PSA complexed to A2M is not immunologically detectable.

Preparation

Specimens should not be drawn immediately after digital rectal examination (DRE), prostatic massage, or transrectal ultrasound (TRUS). PSA sampling should not be performed for at least six weeks after prostatic biopsy.