How reliable is the Free PSA test as a cancer predicator?
It provides useful information on the risk of finding prostate cancer on a biopsy in men whose PSA level is between 2.5 and 10. It is a more robust predictor in the PSA range of 4 to 10 than in the lower range. In the PSA 4-10 range, if the percent free PSA is less than 10%, the likelihood of finding cancer on biopsy is more than 50%; whereas, if the percent free PSA is greater than 25%, the likelihood is less than 10%.
