The analytical and clinical validation of new biomarkers for the early detection of prostate is necessary. (-2)proPSA, total PSA and free PSA values are used to calculate a standardized PHI index linked to a higher probability of a positive biopsy in patients with PSA levels between 3-4 and 10 ng/L, the gray zone for prostate cancer diagnosis. The purpose of this study is to validate the analytical performance of the (-2)proPSA and to determine the predictive value of PHI for the early detection of prostate cancer. Analytical performances are correct. It is not necessary to dilute samples before analysis. The stability of (-2)proPSA is good until at least 3 hours at room temperature before centrifugation. The study of the PSAT, PSAL, (-2)proPSA and PHI values in a population of patients consulting for an early prostate cancer diagnosis shows that the index PHI is the most powerful predictive marker of cancer with an area under ROC curve of 0.70, whereas it is only 0.56 for total PSA.