This panel includes two (2) tests: 1. PSA (prostate specific antigen) blood serum is a non invasive preventive blood test used to detect prostate cancer in men. 2. PSA-f ("free PSA) measures the proportion of free PSA to bound PSA in the total PSA in your blood sample. Combined with the prostate volume, percent free PSA calculation helps reduce the number of biopsies based on "false positive" PSA test results. This may spare you an unnecessary biopsy. High free PSA--above 25%-- usually indicates benign prostate hyperplasia. Low free PSA--below 15%--may indicate prostate cancer.