Prostate is a walnut size gland which helps in production of seminal fluid and control of urination in men. Prostate enlargement and malignancy are a common problem associated with ageing in men. PSA is a protein produced by normal as well as cancerous cells of the prostate gland. Amount of PSA present in the blood is used as a screening test for prostate cancer.
It exists in both bound and free form in the blood. Total PSA is the total amount of both bound and free form of PSA present in the blood, while free PSA test tells us about the free PSA present in the blood. Ratio of free and total PSA is a more sensitive indicator of the presence of malignancy as compared to total or free PSA alone. People with benign enlargement of the prostate have a greater proportion of free PSA as compared to those with malignancy. Additionally, PSA levels may change due to prostate biopsy or hormone therapy.