PSA, Total + %Free
The Free & Total PSA test measures the blood level of PSA, Total & Free. PSA is produced by the prostate gland. High PSA levels are linked to prostate cancer. The % Free PSA measures the PSA level independent of the binding protein level. A low ratio of Free PSA to Total PSA (under 15%) is correlated with a higher risk of prostate cancer. PSA levels are also measured in order to assess the relative risk of prostate cancer recurrence after treatment.