Also known as: PSA, Free:Total Ratio.

A free PSA is primarily ordered when a male has a moderately elevated total PSA. Results give the health professional additional information about whether ther person is at an increased risk of having prostate cancer and aid with the decision of whether to biopsy the prostate. The test was developed to better differentiate between non-cancer-related and cancer-related PSA increases, and operates on the principle that men with prostate cancer will frequently have altered ratios of the two forms of PSA - decreased amounts of free PSA and increased amounts of cPSA.