PSA is organ specific, being produced primarily by prostatic secretory epithelium, but has long been known to be elevated in non‑malignant conditions such as benign prostatic hyperplasia (BPH).
A number of studies have found that the % free PSA was significantly lower in patients having prostate cancer than those with benign disease or normal controls.
The ratio fPSA/tPSA has been demonstrated to improve the sensitivity and specificity in patients with tPSA values in the “gray zone” of 4‑10 ng/mL.
There is an additional £15 phlebotomy fee.
